2001

Wednesday 9 January 2002

Summary

Extremely low annual rainfall in the eastern South Island and parts of the lower North Island, despite wet end-of-year conditions Severe summer–autumn drought, mid-winter freeze Many other extreme events

For the first year of the new millennium, New Zealand’s climate records continued to tumble. Senior climate scientist Dr Jim Salinger said the National Institute of Water and Atmospheric Research (NIWA) analysis of the year’s weather showed new local records being set in some months, both for average and extreme temperature. “2001 was one of the driest years on record in many eastern South Island areas, as well as parts of Wellington, despite wet October-December conditions,” Dr Salinger said.

“The North Island bore the brunt of eleven rainfall/flooding extremes. Tornadoes also featured in 2001, with at least eight reported, along with an unusual number of wind events, many of them causing property damage. The year featured many new climate records and extremes, with five unusually warm months, and two much colder than average months. There were six cold snaps last winter, four with snow and two with extreme frosts. There were at least two widespread and damaging hailstorms, with hailstones the size of golf balls.”

Higher than average pressures occurred from the South Tasman Sea across the lower South Island and east past the Chatham Islands. Pressures were below average in the north Tasman Sea and to the north. This pattern resulted in more frequent easterlies and north-easterlies over the north of the North Island and more settled conditions elsewhere. Analyses of month-by-month records for the year compared with recorded statistics for previous years show:

• The year’s national average temperature was 12.8°C (0.3°C above the 1961–1990 normal).
• The highest annual mean temperature recorded for the year was 16.9°C recorded at CapeReinga.
• The highest recorded extreme temperature for the year was 35.3°C recorded at Timaru Airport on 4 February, and the lowest was –12.2°C at Hanmer Forest on the morning of 5 July.
• Unusually warm in May, August, September, October and December.
• Rather cool in January; July was the coldest in over 30 years.
• Unusually wet with record low sunshine over the North Island in December.
• The driest recorded centre was Alexandra, with only 299 mm of rain for the year.
• North Egmont remained again being the wettest location with an annual total of 7546 mm. Milford Sound only managed 5134 mm in 2001.
• Christchurch was the driest main centre with 405 mm and Auckland the wettest with 1256 mm. Wellington received 1053 mm and Dunedin 515 mm.
• The capital was again the sunniest of the three largest centres with 2094 sunshine hours, followed by Christchurch (2072 hours), and Auckland (1981 hours). Nelson was the sunniest centre in 2001 with 2550 hours, followed by Blenheim with 2484 hours and Motueka with 2430 hours.

For further information, please contact:

Dr Jim Salinger – Principal Scientist, Climate NIWA National Climate Centre – Auckland Phone +64 9 375 2053 [email protected]

Stuart Burgess – Climatologist NIWA National Climate Centre – Wellington Phone +64 4 386 0569 [email protected]

Geoff Baird – Communications Manager Phone +64 4 386 0543 [email protected]

Acknowledgement of NIWA as the source is required.

For more details read on

2001 – Extremely low annual rainfall in the eastern South Island and parts of the lower North Island, despite wet october–december conditions

Severe summer–autumn drought, big mid-winter freeze

Sunny in Nelson, Taranaki, Westland and Southland

The previous La Ni�a faded out in early 2001, and much more anticyclonic conditions than normal across the South Island for the first nine months of the year. This produced one of the driest years since records began in many eastern South Island areas. However, frequent troughs (‘lows’) in the Tasman Sea and over the North Island for the last three months produced a warm and wet end, especially for the North Island. Above average sea temperatures kept temperatures mainly higher than normal over land, and helped produce more stormy conditions from October to December.

2001 was also an extremely dry year in parts of Wellington. Rainfall was well below normal in southern Wairarapa, and below average in most other South Island areas. It was wetter than average in parts of Northland, Coromandel and Bay of Plenty. The severe summer–autumn drought was a major contributor to the extremely low South Island and southern North Island annual rainfall totals”.

The 2001 national average temperature, calculated by NIWA, was 12.8°C, which was 0.3°C above normal, according to NIWA. For New Zealand as a whole, there were eight warmer than average months (including five exceptionally warm months; May, August, September, October and December), and two very much cooler than average months (January and July). 2001 mean temperatures were average to above average in many areas for the year as a whole. However, they were below average in a few eastern districts. It was a sunnier than average year in Nelson, Westland, Taranaki, and Southland, but rather cloudy in eastern Bay of Plenty.

Pressures were higher than normal across the South Island, and the below average to the north of New Zealand, with more easterlies and north-easterlies onto the north, and more settled conditions elsewhere.

NOTE: throughout this report ‘normal’ refers to the 1961–1990 average

Sunny in Nelson, Taranaki, Westland and Southland

Low sunshine values in eastern Bay Of Plenty

2001 was a year with about 105 percent of normal sunshine recorded in Nelson, Taranaki, Westland and Southland. However, sunshine hours were well below average in Bay of Plenty. Near average sunshine hours occurred in other regions. Extremely low annual sunshine for the year 2001 were measured at:

Location	2001 sunshine (hours)	Percentage of normal	Year records began	Comments
Whakatane	2051	88	1957	Lowest

Nelson was the sunniest centre in 2001, recording 2550 hours, followed by Blenheim with 2484 hours, and then Motueka with 2430+ hours. Total sunshine hours for the year 2001 in selected main centres were:

Location	2001 sunshine (hours)	Normal (hours)	Departure from normal	Comments
Auckland	1981	2043	–3%	Below average
Wellington	2094	2048	+2%	Near average
Christchurch	2072	2057	+1%	Near average
Dunedin	Not available	1613
Invercargill	1667	1565	+7%	Above average

Extremely low annual rainfall in the eastern South Island and Lower North Island

“NIWA figures show it was the one of the driest years since records began in many eastern South Island areas, as well as parts of Wellington. It was also a much drier than usual year in southern Wairarapa, and drier than average in most other South Island areas. Rainfall was above average in parts of Northland, Coromandel, and Bay of Plenty”, said Dr Salinger. The severe summer–autumn drought was a major contributor to the extremely low South Island and southern North Island annual rainfall totals”. Extremes of annual rainfall for the year 2001 were measured at:

Location	2001 rainfall (mm)	Percentage of normal	Year records began	Comments
Wellington Airport	742	73	1960	2nd lowest
Hanmer Forest	681	59	1905	2nd Lowest
Waimate	336	53	1898	Lowest
Tara Hills	326	59	1950	Lowest
Wanaka Airport	514	73	1993	Lowest
Dunedin, Musselburgh	515	66	1918	2nd Lowest
Manapouri Airport	873	69	1992	Lowest
Lauder	384	78	1982	3rd lowest
Clyde	329	76	1984	3rd Lowest

Of the four main centres, Christchurch was the driest with 405 mm, and Auckland was the wettest with 1256 mm. Wellington received 1053 mm, and Dunedin 515 mm. Alexandra in Central Otago was the driest location NIWA measured in New Zealand, with only 299 mm. The wettest location in 2001, for which rainfall data are presently available, is North Egmont on the slopes of Mt Taranaki, with a total of 7546 mm. In comparison, Milford Sound received 5134 mm.

Slightly above average temperatures overall

The 2001 national average temperature, calculated by NIWA, was 12.8°C, which was 0.3°C above normal. For New Zealand as a whole, there were eight warmer than average months (including five exceptionally warm months: May, August, September, October and December), and two very much cooler than average months (January and July). Mean temperatures were about 0.5°C above average in parts of Auckland, Coromandel, Waikato, western Bay of Plenty, Wellington, and Nelson, and about 0.5°C below average in coastal areas of southern Hawke’s Bay, and parts of Central Otago. The warmest locale was Cape Reinga, with a mean temperature for the year of 16.9°C.

The highest extreme temperature for the year was 35.3°C recorded at Timaru Airport in very hot north-westerly conditions on 4 February. The lowest recorded temperature for the year was –12.2°C, measured at Hanmer Forest on the morning of 5 July.

Significant weather events – 2001

Five unusually warm months

Four of the eight warmer than average months, had unusually high mean temperatures (the national average temperature being in the top ten, since reliable records began in 1850s). December was very unusual, in that the overnight minima were extremely high. Comments on these are as follows:

May 7th warmest on record

Occasional summer-like temperatures occurred during the first two weeks when temperatures averaged 4°C above average, with many locations recording new extreme maximum May temperatures. Record high May extreme maximum temperatures were recorded at:

Location	Maximum temperature (°C)	Date of occurrence	Year records began
Hokitika Airport	22.6	1	1964
Nelson Airport	22.0	3	1943
Auckland, Henderson	23.9	6	1986
Palmerston Nth. Airport	23.6	6	1962
Palmerston North	25.6	6	1918
Wellington Airport	22.0	6	1962
Kawerau	24.8	7	1954
Levin	22.9	11	1896
Wallaceville	23.3	11	1940
Arapito	23.6	11	1980
East Taratahi	23.7	12	1973

Near or record high mean temperatures (for the full month) occurred throughout much of the North Island, and many northern South Island regions, including parts of Central Otago and inland Southland. The national average temperature was 11.6°C, which was 1.1°C above the 1961–1990 normal, and 10th highest since reliable measurements began in the 1850s.

Unusually high mean May temperatures were recorded at:

Location	Mean temperature May 2001 (°C)	Departure from normal (°C)	Year records began	Comments
Whangarei Airport	15.7	+1.7	1968	Highest
Auckland Airport	15.2	+1.8	1963	Highest
Paeroa	14.5	+2.7	1947	Highest
Tauranga Airport	14.6	+2.1	1913	2nd equal highest
Rotorua Airport	12.0	+1.6	1964	Highest
Taupo Airport	10.9	+2.1	1976	Highest
Hamilton, Ruakura	13.7	+2.2	1907	2nd highest
Hamilton Airport	13.3	+2.3	1971	Highest
New Plymouth	13.7	+1.7	1944	Equal highest
Turangi	11.1	+1.9	1968	Highest
East Taratahi	11.8	+1.9	1973	Highest
Palmerston Nth. Airport	12.8	+2.1	1962	2nd highest
Wellington, Kelburn	12.8	+1.6	1928	3rd highest
Wellington Airport	14.1	+2.1	1962	Highest
Wanganui	13.7	+1.7	1937	2nd highest
Farewell Spit	13.6	+1.8	1971	Highest
Nelson Airport	11.9	+2.0	1943	Equal highest
Chatham Islands	12.2	+1.8	1957	Highest

August 6th warmest on record

The national average temperature of 9.4°C was 0.8°C above the 1961–1990 normal, the highest for August since 1991 and 6th warmest since reliable measurements began in the 1850s. Near or record high mean August temperatures were recorded at:

Location	Mean temperature August (°C)	Departure from normal (°C)	Year records began	Comments
Wellington, Kelburn	10.3	+1.2	1862	3rd equal highest
Wallaceville	10.1	+1.7	1940	Highest
Nelson Airport	9.4	+1.5	1943	2nd highest
Blenheim	9.8	+1.2	1932	2nd equal highest
Chatham Islands	9.5	+1.0	1957	Equal highest

September 8th warmest on record

The national average temperature was 11.2°C, which was 0.9°C above the 1961–1990 normal, and 8th highest since reliable measurements began in the 1850s. Near or record high mean September temperatures were recorded at:

Location	Mean temperature September (°C)	Departure from normal (°C)	Year records began	Comments
Kaitaia Observatory	14.3	+1.4	1943	2nd equal highest
Hokitika Airport	10.9	+1.1	1867	4th equal highest
Milford Sound	10.0	+1.5	1935	Equal highest
Puysegur Point	11.1	+1.9	1978	Highest
Tara Hills	8.9	+1.9	1927	2nd equal highest
Dunedin, Musselburgh	10.7	+1.5	1853	2nd highest
Manapouri	8.8	+1.8	1992	Highest
Queenstown	10.1	+1.7	1871	2nd highest
Queenstown Airport	9.0	+1.7	1968	Highest
Clyde	10.4	+1.6	1983	Highest
Gore	9.8	+1.6	1930	2nd highest
Invercargill Airport	9.9	+1.6	1865	Equal highest
Tiwai Point	10.6	+1.7	1970	Highest

October 3rd warmest on record

This was the 3rd warmest October on record since reliable measurements began in the 1850s. The national average temperature of 13.4°C was 1.3°C above normal. The only other warmer Octobers were those of 1961 (13.8°C) and 1893 (13.7°C). Mean temperatures were much higher than usual in many North Island regions, as well as Nelson, and the South Island West Coast, being at least 1.5°C above normal. Near or record high mean October mean temperatures were recorded at:

Location	Mean temperature October (°C)	Departure from normal (°C)	Year records began	Comments
Kaitaia Observatory	15.8	+1.6	1985	Highest
Kerikeri	15.9	+1.7	1981	Highest
Whangarei Airport	16.5	+2.1	1967	Highest
Warkworth	15.3	+1.7	1972	2nd highest
Auckland, Owairaka	16.2	+2.1	1949	Highest
Auckland	16.2	+1.9	1868	Highest
Pukekohe	16.0	+2.6	1970	Highest
Paeroa	15.6	+1.7	1947	Equal highest
Tauranga Airport	15.5	+1.8	1913	Highest
Hamilton, Ruakura	15.1	+2.0	1907	Highest
Hamilton Airport	14.9	+2.1	1970	Highest
Turangi	13.3	+2.0	1968	Highest
Gisborne Airport	15.6	+1.8	1905	3rd highest
Palmerston North Air	14.0	+1.9	1962	Highest
Wallaceville	13.7	+1.9	1940	Equal highest
Farewell Spit	14.7	+2.1	1971	Highest
Westport Airport	13.9	+2.1	1937	Highest
Arapito	13.9	+1.9	1979	Equal highest
Hokitika Airport	13.1	+2.1	1866	Highest
Milford Sound	11.8	+1.7	1935	Highest
Nelson Airport	14.2	+2.0	1943	Highest

December Extremely high overnight minima

It was extremely warm throughout much of the North Island, due to well above average overnight temperatures. These were the highest on record throughout most of the North Island, and some South Island locations, with values between 2 and 3°C above average. Near or record high mean daily minimum December temperatures were recorded at:

Location	Mean daily minimum temperature	Departure from normal (°C)	Year records began	Comments
Kaitaia Observatory	15.7	+2.2	1985	Highest
Kerikeri	15.0	+2.1	1945	Highest
Whangarei Airport	16.0	+2.2	1967	Highest
Auckland, Henderson	15.3	+2.7	1985	Highest
Auckland, Owairaka	16.1	+2.3	1949	Highest
Auckland Airport	16.5	+2.1	1962	Highest
Pukekohe	15.4	+2.8	1970	Highest
Paeroa	15.1	+2.7	1947	2nd highest
Tauranga Airport	15.7	+2.7	1913	Highest
Hamilton, Ruakura	14.6	+3.2	1906	Highest
Hamilton Airport	14.7	+4.1	1970	Highest
Whakatane Airport	15.5	+3.3	1974	Highest
Rotorua Airport	14.3	+3.0	1964	Highest
Taupo Airport	12.9	+2.6	1976	Highest
Taumaranui	13.9	+2.8	1947	Highest
New Plymouth Airport	15.0	+2.9	1944	Highest
East Taratahi	12.2	+2.8	1972	Highest
Gisborne Airport	15.2	+3.1	1905	Highest
Napier Airport	15.0	+2.4	1973	Equal highest
Napier, Nelson Park	15.8	+2.6	1870	3rd highest
Whakatu	14.1	+1.9	1982	Highest
Paraparaumu Airport	14.6	+2.5	1953	Highest
Palmerston North Airport	13.9	+2.7	1962	Highest
Levin	14.4	+2.4	1895	Highest
Wellington Airport	14.8	+1.6	1962	2nd highest
Normanby	13.9	+2.8	1977	Highest
Wanganui	15.0	+2.2	1937	Highest
Westport Airport	13.5	+2.2	1937	2nd highest
Hokitika Airport	12.6	+2.1	1963	3rd highest
Nelson Airport	14.1	+2.4	1943	Highest
Tara Hills	9.6	+2.0	1949	Highest
Dunedin Airport	10.4	+2.1	1962	2nd highest
Raoul Island	19.8	+1.7	1940	3rd highest
Chatham Islands	13.8	+2.9	1956	Highest

Low temperatures and snowfall

There were six significant cold periods during the tear, two with very extreme frosts and four with snowfall. The central North Island mid-August snowfall event was particularly severe.

January Rather cool

The national average temperature was 15.9°C, 1.2°C below the 1961–1990 normal. It was very much cooler than usual in Canterbury, Otago and Southland, with mean temperatures at least 1.5°C below average, the lowest for January in about 50 years in these regions. Inland areas of Otago were especially cool, with mean temperatures more than 2.5°C below average. Mean temperatures were 1.0 to 1.5°C below average throughout the remainder of the South Island, north Taranaki and Northland. Extremely low January mean temperatures were recorded at:

Location	January mean temperature (°C)	Departure from normal (°C)	Year records began	Comments
Christchurch Airport	15.2	–2.0	1954	2nd lowest
Lincoln	14.9	–1.9	1862	Lowest since 1930
Dunedin	13.3	–1.9	1853	Lowest since 1947
Lauder	13.7	–3.4	1925	Lowest
Clyde	15.2	–2.7	1984	Lowest

May Record screen frosts

Near or record low May screen frosts were measured at:

Location	Minimum temperature (°C)	Date of occurrence	Year records began	Comments
Palmerston Nth. Airport	–3.4	29	1962	2nd lowest
Christchurch Airport	–5.3	26	1954	Lowest
Manapouri	–5.9	29	1962	Lowest

21–27 May Early snowfall

Waves of unseasonably cold southerlies from polar latitudes swept onto southern New Zealand, bringing hail and snow to sea level throughout Southland, and onto the south Otago high country from the afternoon of the 21st. Snowfall continued on the 22nd, lying to a depth of 2 cm along the coast and 8 cm in some inland areas. The cold blast continued on the 23rd, with snowfalls spreading north to the Dunedin hills, Westland and Banks Peninsula. Snowfall to 2.5 cm was measured at Okarito, Westland, an event unheard of before in that area. Snow depths to 5 cm were reported in the Catlins and as much as 20 cm in inland Southland and the Otago high-country. Further snowfall occurred in parts of Central Otago on the 27th.

10 June Snowfall

Bitterly cold southerlies brought snowfall (a few centimetres deep) to sea level in many eastern South Island regions on the 10th, especially in Southland and Otago, temporarily closing Dunedin’s northern motorway. Snow and ice also lay at the Rimutaka Hill summit north of Wellington, and closed the Desert Road.

July Very cold with severe frost

July had a prolonged very cold and frosty start over much of the South Island and many inland and southern North Island regions. The ground frosts were unusually severe at Hanmer Forest where there were 11 consecutive days with grass minimum temperatures below –10.0°C. These produced dangerous icy roads and numerous ice related accidents in many areas, frozen water supplies and water damage in buildings due to burst water pipes. Several small lakes and streams froze over for the first time in many years in some inland South Island regions.

Extremely low July grass minimum temperatures were recorded at:

Location	Grass minimum temperature (°C)	Date of occurrence	Year records began	Comments
Auckland, Henderson	–7.3	12	1986	2nd lowest
Waiouru	–11.0	3	1962	Lowest
East Taratahi	–8.1	4	1972	Equal lowest
Paraparaumu Airport	–9.0	5	1953	2nd lowest
Wallaceville	–9.8	4	1940	Equal lowest
Hokitika Airport	–8.5	4	1971	2nd lowest
Motueka, Riwaka	–9.9	5	1956	3rd lowest
Appleby	–10.7	5	1932	2nd lowest
Nelson Airport	–9.7	4	1943	Equal lowest
Lake Rotoiti	–12.0	4	1966	Lowest
Reefton	–10.0	7	1961	3rd equal lowest
Hanmer Forest	–15.3	5	1930	Lowest
Arthurs Pass	–15.0	9 & 11	1978	Equal lowest
Culverden	–12.0	5	1983	Lowest
Winchmore	–12.4	5	1950	Lowest
Rangiora	–11.0	5	1965	Lowest
Christchurch Airport	–9.6	5	1954	Lowest
Waimate	–10.0	4	1918	3rd equal lowest
Dunedin Airport	–11.2	2 & 16	1963	3rd lowest
Ranfurly	–11.9	3	1975	2nd lowest
Lauder	–11.5	3	1982	3rd lowest

The July national average temperature of 6.8°C was 0.9°C below the 1961–1990 normal and the lowest for July since 1969. Near record low mean July temperatures were recorded at:

Location	Mean temperature July 2001 (°C)	Departure from normal (°C)	Year records began	Comments
Taupo Airport	4.6	–1.5	1976	Lowest
Normanby	6.7	–1.9	1977	Lowest
Castlepoint	8.3	–1.7	1972	Lowest
East Taratahi	6.0	–1.3	1972	2nd lowest
Paraparaumu Airport	6.8	–1.7	1953	Lowest
Motueka, Riwaka	5.5	–1.4	1956	2nd lowest
Blenheim Airport	5.4	–1.5	1941	Lowest
Hanmer Forest	1.4	–2.7	1906	Equal lowest
Christchurch Airport	4.5	–1.3	1954	2nd equal lowest
Queenstown Airport	1.6	–1.6	1969	3rd lowest
Clyde	0.8	–2.5	1983	2nd equal lowest

28–29 July Significant alpine snowfall

Heavy snowfalls were recorded in most mountainous regions, and snow and ice closed Arthur’s Pass. Ruapehu ski field reported its largest snowfall in 20 years.

14–15 August Extensive central North Island snowfall

A severe mid-month storm produced extensive snowfall throughout the central North Island volcanic plateau, with depths of 30 cm at Ohakune, the town being isolated by snow-closed roads. Some of the roads that were closed due to snow and ice were: SH1 along the Desert Road – from the evening of the 14th through to the 16th, SH4 from Raetihi to National Park, SH49 from Waiouru to Ohakune and from Ohakune to Raetihi, and SH5 between Taupo and Napier. Snow also lay (few cm deep) at Mangaweka. The snowfall (20 cm) at Waiouru was reported as being the “biggest and deepest since 1974”.

Drought and record low monthly rainfall

January

January began with a continuation of severe soil moisture deficits in Marlborough and the development of similar conditions in Nelson, north Canterbury and south of Napier. Significant soil moisture deficits also developed throughout Auckland, Waikato, Bay of Plenty, and the southern half of the North Island, and from Nelson to Otago. These conditions reflected the very dry conditions that prevailed in many areas with rainfall less than a quarter of normal in Wellington, Nelson and Marlborough, and half of normal in many other areas.

February

Severe soil moisture deficits continued in Marlborough, Nelson, Canterbury and Wellington, with extreme or very high fire risk. Severe soil moisture deficits extended from Nelson through to North Otago in the South Island, and spread to the Wairarapa in the North Island. Rainfall was below average over the entire South Island, especially in Marlborough, Nelson and Canterbury where totals were much less than 25 percent of normal. It was also very much drier than average in Buller, north Otago and Wellington, with rainfall 50 percent or less than normal. Blenheim’s 2-month rainfall total was only 8 mm; the 2nd lowest for any January through February period there in records going back to 1930. Only 1939 was drier.

March

Virtually no rainfall occurred in many areas of the South Island from Golden Bay across to Nelson, and Marlborough to Southland. Many sites in Canterbury and Otago measured totals of 5 mm or less. Severe soil moisture deficits continued in Marlborough, Nelson, Canterbury and Wellington accompanied by very high or extreme fire risk. The lack of rainfall extended the severe soil moisture deficits in the north and east of the South Island from Nelson to Otago, and these spread to central Hawke’s Bay in the North Island. Rainfall totalled at least 300 mm in the Southern Alps between the 26th and 28th, recharging alpine rivers and bringing some relief to parched east coast areas downstream. However, rivers further east remained at record low levels, with some completely dry. Near or record low rainfall was measured in many areas from Golden Bay across to Nelson, and from Marlborough to inland Southland, with totals much less than 25 percent of normal at most locations. Rainfall was also extremely low in Auckland, and parts of western Northland, with rainfall 25 percent or less of normal. Waikato, eastern Bay of Plenty, Gisborne, central Wairarapa, southern Buller, southern Buller, Westland and the Southern Alps received near normal rainfall. For the year to date, the Wellington January–March total of 61 mm is the lowest since records began in 1862, and the Blenheim 3-month total of 20 mm the 2nd lowest in records going back to 1902.

April

Very low rainfall occurred in many South Island areas, especially in the east from the Marlborough coast to Otago, with most sites recording less than 25 percent of normal. Many sites in Canterbury and Otago measured rainfall totalling 15 mm or less for the second consecutive month. Severe soil moisture deficits continued in Canterbury, Otago, and parts of Marlborough. East coast rivers remained at abnormally low levels. Rainfall was also extremely low in Wellington where it was less than 20 percent of normal. Significant soil moisture deficits persisted in Wellington and extended into Wairarapa. Of special note, rainfall for the year to date was the lowest in more than 100 years in both Wellington (77 mm), and Christchurch (60 mm), and the lowest in more than 60 years throughout much of Nelson and Marlborough (Blenheim measured only 38 mm). At the same time as the east had been extremely dry, it was also one of the driest in almost 40 years of measurement at Hokitika.

May

Soil moisture conditions were still unusually dry for the time of year in Marlborough, north and central Canterbury, where they were still in moderate to severe deficit. Low rainfall occurred in Marlborough, with totals about 50 percent of normal.

June

Soil moisture conditions were still low for the time of year in parts of north Otago.

August

Rainfall in parts of Canterbury and north Otago was well below average, being 50 percent or less than normal. It was also below average in the Waitaki and Clutha lakes catchments. Soil moisture continued lower than normal in central Marlborough, around Christchurch and north Canterbury, and in north and central Otago.

September

Rainfall was extremely low throughout much of the south and west of the North Island, as well as Nelson, Marlborough, Canterbury, and Otago, all recording less than 25 percent of normal, with totals of less than 20 mm. Near or record low rainfall was measured at many locations within these regions. Soil moisture deficits were significant for the time of year in central Marlborough, around Christchurch and north Canterbury, and north and central Otago.

October

Only half the normal rainfall occurred in the Southern Lakes. Soil moisture deficits remained very high for the time of year in inland areas of both Otago and south Canterbury.

Record low monthly rainfall

Some locations measured extraordinary low rainfall at various times during the year. These were:

Location	Rainfall (mm)	Percent of normal	Year records began	Comments
January
Levin	12	14	1896	2nd lowest
Kelburn, Wellington	13	16	1862	5th lowest
Wellington Airport	7	10	1960	Lowest
Wallaceville	20	23	1924	Lowest
Blenheim	2	6	1930	2nd equal lowest
Blenheim Airport	5	9	1941	3rd lowest
Febuary
Westport Airport	39	28	1945	Lowest
Lake Rotoiti	7	7	1934	Lowest
Moteuka, Riwaka	2	3	1943	2nd lowest
Nelson Airport	6	11	1941	3rd equal lowest
Blenheim Airport	3	9	1941	4th lowest
Hanmer Forest	7	10	1905	2nd lowest
Kaikoura	13	24	1950	2nd lowest
Winchmore	11	20	1947	2nd lowest
Christchurch Airport	4	10	1944	Lowest
Christchurch Gardens	4	10	1864	3rd equal lowest
Timaru Airport	9	19	1957	Lowest
Waimate	10	20	1898	Equal lowest
Manapouri	15	19	1914	3rd lowest
March
Dargaville	17	19	1943	Equal lowest
Auckland, Owairaka	13	13	1949	Lowest
Waiouru	22	27	1961	2nd lowest
Blenheim Airport	8	13	1941	3rd lowest
Winchmore	4	7	1947	Equal lowest
Lincoln	4	7	1881	Lowest
Akaroa, Rue Lavaud	3	3	1978	Lowest
Timaru Airport	4	8	1957	Lowest
Tara Hills	1	3	1950	Lowest
Dunedin Airport	8	12	1963	Equal lowest
Musselburgh	2	3	1918	Lowest
Gore	18	22	1943	2nd lowest
April
Cape Palliser	5	6	1930	Lowest
Wellington, Kelburn	16	15	1862	Equal lowest
Wellington Airport	11	13	1960	2nd lowest
Westport Airport	53	28	1944	2nd lowest
Hanmer Forest	20	19	1905	3rd lowest
Christchurch Airport	7	13	1944	Lowest
Christchurch Gardens	5	8	1864	2nd lowest
Lincoln	5	8	1881	Lowest
Akaroa, Rue Lavaud	12	14	1978	Lowest
Musselburgh	21	32	1918	3rd lowest
Queenstown Airport	11	20	1969	Lowest
June
Kerikeri	59	33	1936	3rd lowest
Whangarei Airport	39	22	1937	2nd lowest
Mokohinau Island	21	16	1935	Lowest
Warkworth	75	42	1972	Lowest
Whitianga	45	24	1942	2nd equal lowest
Te Puke	64	35	1973	Lowest
Whakatane Airport	44	36	1975	Lowest
July
Westport Airport	36	19	1944	Lowest
Lake Rotoiti	15 to 30	12	1934	Lowest
Hokitika	28	12	1866	Lowest
Motueka	36	23	1943	2nd lowest
Nelson Airport	8	9	1941	Lowest
Blenheim Airport	12	17	1941	Lowest
Tara Hills	3	9	1950	Lowest
Manapouri	28	31	1991	Lowest
September
Pukekohe	48	39	1970	Lowest
Taupo Airport	19	25	1976	Lowest
Taumarunui	19	13	1913	Lowest
Turangi	44	31	1968	Lowest
Ohakune	9	7	1975	Lowest
Waiouru	20	22	1950	Lowest
Wanganui	5	7	1890	Lowest
Palmerston N Airport	12	15	1943	Lowest
Levin	9	10	1895	Lowest
Waione	0	0	1992	Lowest
East Taratahi	16	18	1972	Lowest
Palliser	9	12	1930	Lowest
Paraparaumu Airport	16	19	1945	Lowest
Wallaceville	10	10	1924	Lowest
Wellington Airport	8	9	1960	Lowest
Lake Rotoiti	32	23	1934	Lowest
Nelson Airport	21	26	1941	3rd lowest
Blenheim	13	28	1930	3rd lowest
Blenheim Airport	11	18	1941	3rd lowest
Hanmer Forest	10	11	1905	Lowest

Floods and high rainfall

There were at least ten high-rainfall/flood-producing events during 2001. These were most frequent in the North Island. The most significant episodes are listed below.

11 & 17 February

High rainfall occurred in Coromandel on the 11th, Whitianga recorded 120 mm. Further high rainfall occurred in Bay of Plenty and Gisborne on the 17th, Whakatane recording 130 mm.

12–13 April

The remnants of tropical cyclone ‘Sose’ produced high rainfall in the Bay of Islands, Coromandel, and Bay of Plenty over the night of 12/13 April. Significant surface flooding resulted in Keao where rainfall totalled 200 mm in less than 18 hours, and at Whitianga where 132 mm was measured in 24 hours.

2 May

High intensity rainfall resulted, within a few hours, in widespread surface flooding and created chaos for Auckland traffic on 2 May. Water, in places, on the southern motorway was as high as car bonnets, bringing traffic to a stop. Rainfall totalling 30 mm was recorded at Whangaparoa in the hour to 5pm.

12 May

Heavy rainfall and surface flooding occurred on 12 May in Auckland, the Nelson-Takaka, and eastern Bay of Plenty-Opotiki/Ohopi areas (where rainfall as high as 60 mm in 3 hours was reported).

30 May

Extreme high intensity rainfall occurred at Leigh (north of Auckland) on 30 May. Torrential rainfall totalling 109 mm was measured in just one hour (between 1.30 and 2.30 am), superseding the previous non-mountainous New Zealand record for a one-hour event of 107 mm measured at Whenuapai on 16 February 1966. There was widespread damage to local roads, problems with drainage systems, and water flowed on torrents over an already saturated ground surface.

30–31 August

Heavy rainfall, totalling as much as 150 mm, was reported in the Coromandel over the night of 30^th/31^st August. It was also very wet, with totals ranging from about 50–100 mm, throughout Auckland.

1 & 5 September

High intensity rainfall occurred in Warkworth on the 1st, with totals of 36 mm in one hour, 57 mm in two hours, and 154 mm in 24 hours. Further heavy rainfall, with surface flooding occurred throughout Northland on the 5th, with rain as high as 25 mm in an hour, and temporary closure of a number of roads. Many sites in the region measured rainfall totalling between 75 and 100 mm in the 24 hours to 9 am on the 5th. Heavy rainfall and surface flooding also occurred in the Auckland region.

9–10 October

Heavy rainfall at Whakatane totalled 101 mm for the 24 hours to 9 am on the 10th.

22 November

High rainfalls resulted on the 22nd with totals from 50 to 100 mm throughout the Wellington-Hutt Valley region (where a few slips and surface flooding resulted, causing some road closures and traffic delays). Water was knee-high on a Newlands Road. Much of the Wellington rainfall occurred within six hours.

2 December

High rainfall occurred throughout Northland. The Awanui River peaked 7 metres above normal, blocking off parts of SH 12 due to flooding.

Record high monthly rainfall

Some locations experienced extraordinary high rainfall at various times during the year. These were:

Location	Rainfall (mm)	Percent of normal	Year records began	Comments
February
Whitianga	270	281	1942	2nd highest
Tauranga Airport	268	325	1898	2nd highest
Whakatane	310	426	1992	Highest
April
Kerikeri Airport	383	320	1978	2nd highest
Tauranga Airport	348	359	1898	2nd highest
Whakatane	233	314	1992	Highest
May
Cape Reinga	202	231	1920	3rd highest
Warkworth	368	304	1972	Highest
Auckland Airport	210	211	1962	Highest
Whitianga Airport	331	229	1991	Highest
Waihi	500	285	1889	2nd highest
Rotorua Airport	335	297	1964	Highest
Taupo Airport	139	201	1976	Highest
October
Te Paki, Far North	201	275	1931	Highest
Palmerston N. Airport	137	190	1943	2nd highest
Appleby	219	243	1932	2nd highest
Nelson Airport	286	321	1941	Highest
Blenheim Airport	178	278	1941	Highest
Blenheim Research	161	286	1930	Highest
November
Paraparaumu Airport	168	205	1945	3rd highest
December
Kerikeri Airport	270	247	1978	Highest
Manukau Heads	174	207	1935	2nd highest
Motu	449	261	1990	Highest
New Plymouth Airport	346	318	1944	2nd highest
Taumarunui	308	225	1913	2nd highest
Turangi	314	246	1968	Highest
Castlepoint	165	258	1902	3rd highest
East Taratahi	137	253	1972	Highest
Napier Airport	188	254	1950	2nd highest
Napier, Nelson Park	172	259	1870	2nd highest
Whakatu	143	467	1982	Highest
Mahia	165	255	1990	Highest
Wanganui	173	224	1890	2nd highest
Wellington Airport	134	181	1960	2nd highest
Lake Rotoiti	324	220	1933	Highest
Reefton	335	197	1904	2nd highest

Tornadoes, gales and high winds

16 January

Winds gusting to 170 km/h, recorded at Taiaroa Head, Otago Harbour, lashed the South Island on 16 January, causing power blackouts, blew fruit off trees in Central Otago and yachts off their moorings. Wellington was also battered by winds up to 140 km/h, lifting roofs and bringing down power lines. A wind gust of 161 km/h was recorded at Puysegur Point, at the southwest tip of the South Island.

28–29 March

A tornado, with severe winds, ripped through part of Greymouth at about 4 am on the morning of 28 March. Several houses and garages were badly damaged by the wind and flooded by heavy rainfall accompanying the tornado. High winds from the northwest, gusted to 143 km/h in Kaikoura over the night of 28/29 March, damaging power lines resulting in loss of electricity to more than 300 houses. An injured passenger was airlifted from a boat in Foveaux Strait in rough conditions on the same night.

4–5 May

High winds buffeted western Bay of Plenty over the night of 4/5 May, with a tree uprooted and power lost to parts of Tauranga. One house lost part of its roof.

10 June

Southerly gales affected Cook Strait, disrupting ferry services.

28–29 July

High winds and heavy seas buffeted southern and eastern coasts on the 28th and 29th, with 11-metre swells in Cook Strait. One of the Cook Strait fast ferries was forced to turn back to Wellington, with many other ferry sailings cancelled, disrupting thousands of passengers.

14–15 August

A depression developed on a southerly front on the 14th, deepening later just east of Gisborne. The associated weather system produced southerlies of violent-storm force (mean wind speeds to 117 km/h, and gusts to 189 km/h) in Cook Strait, with huge swells and 11-metre waves. These resulted in the cancellation of ferry crossings on the 15th.

23 August

High winds, reported to be those of a tornado or waterspout, lifted a garage roof and caused damage to trees and fences from Katikati to Omokoroa (western Bay of Plenty). The severe winds at Omokoroa (at 7.15 pm) lasted less than a minute. Parts of a fence were later found more than 100 metres away. The damaging winds were followed about 45 minutes later by thunder, lightning, heavy rainfall and hail.

9 October

High winds occurred with the passage of a 100-metre-wide waterspout/tornado through Cable Bay, Northland, at about 12.30 pm on the 9th, resulting in damage to about 19 houses, some extensive. Another tornado was report on the same day, at Mata, 22 km southeast of Whangarei, moving a barn 100 metres across a paddock.

22 October

High winds and heavy rainfall buffeted the Gisborne region over the night of the 22nd, resulting in extensive damage in kiwifruit orchards.

31 October

Squally north-westerlies with isolated thunderstorms and heavy rainfall affected many northern and western North Island regions, with the approach of an active cold front, during the night of 31 October. Parts of Auckland appeared to be worst affected with fallen trees, and at least 10 houses having damaged roofs, associated with the passage of a ‘vortex’ and wind gusts to about 150 km/h. Fallen trees were also reported in Tauranga and Rotorua.

4 November

Four tornadoes were sighted at Awakeri, near Whakatane; one totally destroyed a shed on a farm, just missing nearby residents.

17 November

Storm-force southerlies buffeted Cook Strait, with wind gusts to 198 km/h at Baring Head.

Severe or damaging hail storms

7–8 January

A sudden and violent hailstorm, lasting about 10 minutes occurred in the Masterton area about 6 pm on 7 January. Hailstones, some the size of golf balls (up to 4 cm in diameter) were reported. On two orchards all the apple and pear crops were lost, with severe damage to fruit in others. Over half the grapes were lost in one orchard. The severe hailstorm also broke windows and skylights, and damaged cars. The overall estimate of losses is $5 million. Golf ball-size hailstones were reported at Alexandra on 8 January, causing significant damage to some cherry crops.

28 December

Hail lay 4 cm deep in parts of Rangiora following a convectional storm during the afternoon.

Sunshine extremes

Some locations incurred extremes of sunshine hours at various times during the year. These were:

Location	Sunshine Total (hrs)	Percent of normal	Year records began	Comments
March
Wellington, Kelburn	248	134	1928	Highest
Nelson Airport	279	137	1949	Highest
Invercargill Airport	178	135	1932	2nd highest
May
Whakatane	114	67	1957	Lowest
Queenstown	62	70	1930	3rd lowest
July
New Plymouth	195	144	1915	2nd highest
Hokitika	193	160	1913	2nd highest
Nelson Airport	207	134	1949	2nd highest
October
New Plymouth Airport	149	79	1973	Lowest
Wellington, Kelburn	125	64	1928	2nd lowest
Christchurch Airport	143	70	1949	Equal lowest
November
Whakatane	163	74	1957	3rd lowest
Blenheim	183	78	1930	3rd lowest
December
Kaitaia Observatory	163	75	1985	Equal lowest
Whakatane	135	59	1957	Lowest
Taumarunui	111	58	1947	Lowest
New Plymouth Airport	165	71	1972	Lowest
Paraparaumu Airport	135	60	1953	Lowest
Wellington, Kelburn	153	62	1928	2nd lowest
Hokitika Airport	123	63	1964	Lowest
Nelson Airport	164	68	1948	Lowest

For further information, please contact:

Dr Jim Salinger – Principal Scientist, Climate NIWA National Climate Centre – Auckland Phone +64 9 375 2053 [email protected]

Stuart Burgess – Climatologist NIWA National Climate Centre – Wellington Phone +64 4 386 0569 [email protected]

Geoff Baird – Communications Manager Phone +64 4 386 0543 [email protected]

Acknowledgement of NIWA as the source is required.