March 2003

Tuesday, 1 April 2003
Exceptionally dry in Wanganui, Manawatu, Wairarapa, and Otago
End of month rainfall brings relief to areas in extreme soil moisture deficit in Canterbury, but Wanganui, Manawatu, Horowhenua, Marlborough and Otago still in significant deficit
Record high rainfall in parts of Northland
The warmest month of the year with record high mean temperatures in inland Otago
The sunniest March ever in Kapiti, Wellington, and Dunedin, and extremely sunny over the rest of central and southern parts
For much of New Zealand, March was a month of new records produced by very settled, e

Tuesday, 1 April 2003

Exceptionally dry in Wanganui, Manawatu, Wairarapa, and Otago End of month rainfall brings relief to areas in extreme soil moisture deficit in Canterbury, but Wanganui, Manawatu, Horowhenua, Marlborough and Otago still in significant deficit Record high rainfall in parts of Northland The warmest month of the year with record high mean temperatures in inland Otago The sunniest March ever in Kapiti, Wellington, and Dunedin, and extremely sunny over the rest of central and southern parts

For much of New Zealand, March was a month of new records produced by very settled, extremely dry and unusually sunny weather patterns, except in the north. Significant rainfall brought relief to many drought-affected areas at the end of the month.

Very little rainfall occurred, at many locations in the south and west of the North Island, from Wanganui to Wellington, and throughout much of Nelson, Marlborough, Canterbury and Otago until after 27 March. Until then most stations in these regions recorded totals of 10 mm or less. Christchurch Airport and Lauder, had no measurable rainfall in this period. Parts of Manawatu, Horowhenua, and Kapiti had not had a day’s rainfall exceeding 10 mm since Christmas or before. Substantial rainfall, totalling 50–90mm, occurred throughout north Canterbury from the 28th to the 30th.

For the month, rainfall was less than 25 percent (quarter) of average in Central Otago, and less than 50 percent (half) of average at most locations in the southern half of the North Island, and over much of the South Island. Rainfall was near average in Waikato, and in much of Bay of Plenty. In contrast, rainfall was more than twice (200 percent) average in parts of Northland, and above average in Auckland, Coromandel, and areas of Gisborne, due to significant amounts that occurred during the second and last week of the month. Rainfall was also above average in north Canterbury.

Significant soil moisture deficits continued throughout the north and east of the South Island, from Nelson to Otago, as well as the southwest North Island from Wanganui to Wellington, and Wairarapa. The end-of-month rainfall resulted in major relief for Nelson and north Canterbury soils.

Mean temperatures were above average in the west of the North Island from Auckland to Wellington, and over much of the South Island, but it was very much warmer than usual, with mean temperatures at least 1.5°C above average in the Southern Lakes district and Central Otago. The national average temperature of 16.7°C was 0.8°C above normal, making March 2003 the warmest month this year and warmer than the usual months of summer.

Extremely high sunshine and solar radiation totals were recorded at many locations throughout the south and west of the North Island and in the South Island. Sunshine hours were below average in Northland, Auckland, and Gisborne.

While anticyclones (‘highs’) dominated New Zealand’s March climate pattern, they were more frequent than average to the south and east of the South Island. Below average pressures prevailed between Northland and New Caledonia. This pattern produced more frequent airflow from the northeast than is usual over New Zealand.

Well below average rainfall in the Southern North Island and over much of the South Island Above average rainfall in the north of the North Island

Rainfall totals were less than 50 percent (half) of average at most locations in the southern half of the North Island, and over much of the South Island (apart from Nelson and Canterbury). Rainfall was less than 25 percent (quarter) of average in Central Otago.

Contrasting totals, at least 200 percent of average, occurred in parts of Northland, with at least 125 percent of average rainfall in Auckland, Coromandel, areas of Gisborne, and in north Canterbury. Totals were near average in Waikato, much of Bay of Plenty, and much of Canterbury.

Rather low March rainfall was recorded at:

Location March rainfall (mm) Percentage of normal Year records began Comments
East Taratahi 16 33 1973 Lowest
Haast 106 29 1941 3rd lowest
Tara Hills 10 19 1949 3rd equal lowest
Middlemarch 6 11 1907 Well below average
Dunedin Airport 12 19 1963 3rd lowest
Queenstown Airport 16 23 1969 Lowest
Lauder 8 12 1943 Well below average
Clyde 9 21 1983 Lowest
Invercargill Airport 33 35 1940 3rd lowest
Tiwai Point 38 41 1971 3rd lowest
Nugget Point 20 24 1930 3rd lowest

High March rainfall was recorded at:

Location March rainfall (mm) Percentage of normal Year records began Comments
Kaitaia Observatory 226 263 1986 Highest
Kerikeri EWS 335 204 1982 2nd highest
Kerikeri Airport 395 237 1978 2nd highest
Kaikohe 245 186 1973 Highest
Whangarei Airport 248 189 1937 Well above average
Auckland, Owairaka 196 207 1949 Well above average

Extremely sunny over much of the South Island and Southwestern North Island

Sunshine and solar radiation totals were well above average (at least 120 percent of normal) throughout the south and west of the North Island, and almost all of the South Island, with near or record high totals recorded at many locations in these regions. Sunshine hours were less than 90 percent of average in Northland, Auckland, and Gisborne.

Near or record high March sunshine hours were recorded at:

Location March sunshine (hours) Percentage of normal Year records began Comments
Paraparaumu Airport 280 150 1953 Highest
Wellington, Kelburn 267 144 1928 Highest
Arapito 226 to 29th 148 1980 Highest
Hokitika Airport 235 145 1964 2nd highest
Nelson Airport 273 135 1949 2nd highest
Dunedin, Musselburgh 203* 153 1948 Highest
Invercargill Airport 178 135 1932 2nd equal highest

* Missing a day

Near or record high March solar radiation was recorded at:

Location March solar radiation (MJ/m2) Percentage of normal Year records began Comments
Palmerston North Airport 17.7 120 1992 Highest
Levin 18.0 122 1972 Highest
Wanganui, Spriggens Park 18.1 116 1997 Highest
Hokitika Airport 16.2 118 1969 3rd equal highest
Nelson Airport 18.7 120 1969 3rd highest

Average or above average temperatures in most regions

Mean temperatures were at least 0.5°C above average in the west of the North Island from Auckland to Wellington, including Wairarapa, and over much of the South Island. It was very much warmer than usual, with mean temperatures at least 1.5°C above average in the Southern Lakes district and Central Otago. Temperatures were near average in Northland, Coromandel, Bay of Plenty, Gisborne, Hawke’s Bay, Buller, Westland, and Marlborough.

Near or record high mean March temperatures were recorded at:

Location Mean temperature Departure (°C) Records began Comments
Palmerston North Airport 18.3 +1.9 1962 3rd equal highest
Farewell Spit 18.4 +1.7 1977 Highest
Wanaka Airport 16.1 +2.2 1993 Highest
Queenstown 16.8 +2.4 1872 Highest
Queenstown Airport 14.8 +1.5 1969 2ndequal highest
Lauder 15.4 +2.4 1982 Highest
Clyde 16.3 +2.0 1983 Highest

Afternoon maxima were very much higher than average in the southwest of the North Island from Manawatu to Kapiti, including parts of the central North Island Volcanic Plateau and Wairarapa, inland south Canterbury, and Otago.

Near or record high mean daily maximum March temperatures were recorded at:

Location Mean daily maximum temperature Departure (°C) Records began Comments
Turangi 22.5 +1.5 1968 3rd highest
East Taratahi 24.1 +2.5 1973 2nd equal highest
Paraparaumu Airport 22.2 +1.9 1953 2nd highest
Palmerston North Airport 24.5 +3.0 1962 2nd highest
Levin 23.8 +3.1 1896 Equal highest
Hanmer Forest 23.7 +3.0 1906 2nd highest
Tara Hills 22.5 +2.5 1950 Highest
Wanaka Airport 23.2 +2.4 1993 Highest
Manapouri airport 19.9 +1.9 1991 2nd highest
Queenstown 23.4 +3.6 1872 Highest
Queenstown Airport 21.0 +2.1 1969 Highest
Lauder 22.8 +3.0 1982 Highest
Clyde 23.4 +2.8 1983 Highest
Ettrick 22.4 +2.3 1985 2nd highest

Highlights

Extreme temperatures

  • The highest air temperature for the month was 31.8°C, recorded at Hanmer Forest on the 21st. The highest March air temperature on record there is 32.4°C.
  • Heat-wave like conditions occurred in the southwest North Island on the 2nd, Levin recording 31.0°C, a new record high temperature extreme for any time of the year there in records going back to 1896.
  • The lowest air temperature for the month was –1.0°C, recorded at both Manapouri Airport and Lumsden on the 18th. The lowest March air temperatures on record at Manapouri Airport and Lumsden are –5.5°C and –2.9°C respectively.

Heavy rainfall

  • Heavy rainfall occurred in the Bay of Islands, parts of Auckland, Coromandel, and areas of Gisborne during the second week of the month, and in Northland during the last week. Rainfall totals recorded for these events:
    Location Rainfall total (mm) Date of occurrence
    Kerikeri Airport 178.0 9–10 March
    Owairaka, Auckland 129.4 10–11 March
    Whitianga Airport 108.4 10–11 March
    Gisborne Airport 83.2 11–12 March
    Kaitaia EWS 151.0 27 March
    Kerikeri Airport 116.4 27 March
    Kaikohe 126.0 27 March
  • Surface flooding occurred in parts of Northland and Auckland on the 27th and 28th, being widespread in Kaitaia.

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.

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