October 2003

Saturday, 1 November 2003
Rainfall: Near or above average over much of the North Island; below average in Hawke’s Bay, Westland, Fiordland, Canterbury, Otago and Southland
Temperatures: Below average temperatures over much of the North Island, and the eastern South Island (Marlborough, Canterbury and Otago)
Sunshine: above average in most regions, especially Southland
October was a month of mixed weather. It was wet and rather unsettled in many areas during the first two weeks. However, mainly dry settled conditions prevailed for the rest of the month.

Saturday, 1 November 2003

Rainfall: Near or above average over much of the North Island; below average in Hawke’s Bay, Westland, Fiordland, Canterbury, Otago and Southland

Temperatures: Below average temperatures over much of the North Island, and the eastern South Island (Marlborough, Canterbury and Otago)

Sunshine: above average in most regions, especially Southland

October was a month of mixed weather. It was wet and rather unsettled in many areas during the first two weeks. However, mainly dry settled conditions prevailed for the rest of the month. The month’s rainfall was well above average in parts of Northland, Coromandel, Bay of Plenty, Wairarapa and Wellington, and well below average in Hawke’s Bay, inland south Canterbury and the Southern Lakes. Soil moisture deficits are increasing throughout Otago and South Canterbury, being significant in some inland areas there. Deficits are also appearing in Marlborough, and Hawke’s Bay. The month was cooler than usual over much of the North Island and the eastern South Island. Sunshine totals were above average throughout much of New Zealand. The October climate patterns were associated with more frequent depressions (‘lows’) than usual in the north Tasman Sea off the Australian coast, with more frequent easterlies and northeasterlies over much of New Zealand. More anticyclones (‘highs’) prevailed to the southeast so that westerlies were noticeably less frequent than normal.

Highlights

  • The lowest air temperature for October 2003 was –6.9°C, recorded at The Chateau, Tongariro, on the 6th, along with other frosts and unusually low temperatures on the same day in many other North Island and southern South Island areas. Some Bay of Plenty kiwifruit orchards and Marlborough stone fruit orchards were affected by frosts. The highest air temperature for the month was 27.0°C, recorded at Alexandra on the 20th.
  • A severe high intensity rainfall event producing 200–300 mm in the Tararuas, along with gale force northerly winds, occurred on 3 October, contributing to a devastating land and mudslide at Paekakariki, followed by significant snow to high country areas in and near the Canterbury foothills; thousands of lambs were lost due to exposure.
  • Christchurch was the driest of the four main centres, and Wellington the wettest. Rainfall was above average in Auckland and Wellington, and near average in Christchurch and Dunedin. Mean temperatures were near average in Wellington, but below average in the other centres, especially Christchurch. Sunshine hours were above average in Christchurch and Dunedin, and near average in Auckland and Wellington.

Rainfall

Rainfall was near or above average over much of the North Island and northern South Island regions, and below or near average throughout the South Island. Parts of Northland, Coromandel, Bay of Plenty, Wairarapa and Wellington recorded about 200 percent (double) of average rainfall, while totals were 75 percent or less (three quarters) of average in Hawke’s Bay, inland south Canterbury and the Southern Lakes, Westland, and Fiordland. Near average rainfall occurred elsewhere.

Temperatures

Mean temperatures were at least 0.5°C below average throughout most of the North Island and the east of the South Island from coastal Marlborough to Otago, but near average in south Taranaki, Buller, Nelson, Buller, Westland, Fiordland and much of Southland. The October national average temperature of 11.8°C was 0.3°C below normal.

Sunshine

Sunshine totals were above average throughout much of New Zealand, especially Southland. Sunshine was near normal in Northland and Auckland.

Near or above average rainfall over much of the North Island

Below or near average rainfall throughout the South Island

October rainfall was near or above average over much of the North Island and northern South Island regions, and below or near average over much of the South Island. Northland, Coromandel, Bay of Plenty, Wairarapa and Wellington all recorded between 125 and 225 percent (one and a quarter to two and a quarter) of average rainfall. Contrasting well below average rainfall occurred in inland south Canterbury and the Southern Lakes, all with totals 50 percent (half) or less of average. Rainfall was less than 75 percent of average in Hawke’s Bay, Westland, Fiordland, and much of Southland and Otago. Rainfall was near average elsewhere.

Near or record high October rainfall was recorded at:

Location October rainfall (mm) Percentage of normal Year records began Comments
Whakatane Airport 204 204 1975 Well above normal
Motu 392 233 1991 Highest
East Taratahi 118 183 1972 Well above normal
Palliser, Ngawi 171 248 1930 Well above normal

Very low October rainfall was recorded at:

Location October rainfall (mm) Percentage of normal Year records began Comments
Tekapo 12 23 1925 Well below normal

Cooler over much of the North Island and eastern South Island

Mean temperatures were at least 0.5°C below average throughout most of the North Island and the east of the South Island from coastal Marlborough to Otago. Temperatures were at least 1.0°C below average in parts of Auckland, Gisborne, Hawke’s Bay, coastal areas of Wairarapa and Wanganui, the Christchurch area and parts of Central Otago. Temperatures were near average in south Taranaki, Buller, Nelson, Buller, Westland, Fiordland and much of Southland.

Near record low October air temperatures were recorded at:

Location Mean temperature Departure from average (°C) Records began Comments
Auckland, Henderson 13.2 –1.8 1986 3rd lowest

Sunnier in most regions, especially Southland

Sunshine totals were above average (at least 110 percent of normal) throughout much of New Zealand, especially in Southland. Sunshine was near normal in Northland and Auckland.

High October sunshine was recorded at:

Location October sunshine (hours) Percentage of normal Year records began Comments
Taumarunui 192 129 1947 Well above normal
Dunedin 194 126 1948 4th equal highest
Invercargill 208 133 1932 3rd highest

October climate in the four main centres

Of the four main centres, Christchurch was the driest, with 48 mm. August rainfall was above average in Auckland and Wellington, and near average in Christchurch and Dunedin. Mean temperatures were near average in Wellington, but below average in the other centres, especially Christchurch. Sunshine hours were above average in Christchurch and Dunedin, and near average in Auckland and Wellington.

  Aucklanda Wellington Christchurchb Dunedin
October mean temp. (°C) 13.2 11.9 10.5 10.0c
Dep. from normal (°C) –0.8 –0.2 –1.4 –0.4
  Below average Near average Well below average Below average

October rainfall (mm) 127 150 48 55c
% of normal 136 152 108 92
  Above average Above average Near average Near average

October sunshine (hours) 183d 192 235 No data
% of normal 96 98 115
  Near average Near average Above average Above average

a Mt Albert, b Christchurch Airport, c Dunedin Airport, d Whenuapai

Highlights and extreme events

  • The lowest air temperature for October 2003 was –6.9°C, recorded at The Chateau on the 6th, and –6.8°C at Waiouru. The latter was the lowest on record there in October, in records that commenced in 1966. Other unusually low air temperatures also occurred (mainly on the 6th) at the following locations:
    Location Min. (°C) Date Records Began Comments
    Te Puke 0.0 6 1973 2nd lowest
    Gisborne Airport –0.4 6 1905 2nd equal lowest
    Rotorua Airport –1.9 6 1964 2nd lowest
    Waiouru –6.8 6 1966 Lowest
    Palmerston N. Airport –1.6 6 1963 3rd lowest
    Hanmer Forest –5.5 6 1906 Lowest
    Wanaka Airport –2.9 6 1992 Lowest
    Queenstown Airport –3.7 6 1968 Lowest
    Ranfurly –4.8 5 1975 3rd lowest

    Near or record low October grass minimum temperatures were recorded at:

    Location Grass min. (°C) Date Records began Comments
    Motueka, Riwaka –5.0 6 1956 3rd lowest
    Mt. Cook Village –9.6 6 1931 2nd lowest
    Winchmore –7.9 6 1950 3rd lowest
  • The highest air temperature for October 2003 was 27.0°C, recorded at Alexandra on the 20th.
  • High intensity rainfall associated with the approach of an active frontal system occurred on 3 October, after weeks of wet weather, contributing to a huge land and mudslide across SH1 at Pakekakariki. Exceptionally high 48-hour rainfall totals in excess of 200–300 mm were recorded in the Tararua Ranges over 3–4 October. Other high rainfall totals, exceeding 100 mm, recorded during the event of 3 October were:
    Location Rainfall (mm)
    Motu 177
    Taumarunui 101
    Stratford 116
    Paekakariki Hill 119
    Wallaceville 108

    Gale force northerly winds (with gusts between 130 and 140 km/h in and about Cook Strait) and high seas accompanied the rainfall.

  • This resulted in the closure of state highway and main trunk railway north of Wellington. Other routes out of Wellington were also closed, and the cancellation of two inter-island ferry crossings occurred. Two people were killed in a freight plane, possibly hit by lightning, as it crashed in the sea off the Kapiti coast. Farther south, a man drowned at sea off the Kaikoura coast. In the north, a woman was swept downstream in a flooded ford near Coroglen (in the Coromandel) on the 4th. A state of emergency was declared in Paekakariki as sewage and contaminated mud and water (up to waist deep) spread through houses, of which more than 20 were evacuated and 8 left uninhabitable. Almost every business in Paekakariki was flooded, and several cars were covered by mud and rubble. Around 10,000 cu m of gravel poured down Paekakariki Hill during the event. Initial damages due to the event were estimated to be at least $2.5 million for Paekakariki and another $3 million for the remainder of New Zealand. On the 4th snow occurred on the Rimutaka and Orongaronga ranges, and settled down to 800 m on the central North Island plateau, with flurries in Taihape, Taumarunui, and the Wellington hill suburbs of Brooklyn, Karori and Broadmeadows. On the 5th snow fell down to 200 m in the South Island high country of Canterbury, Otago, and Southland, where thousands of newborn lambs died due to exposure. A snow depth of 20 cm was reported at Oxford, near the Canterbury foothills. Snow closed part of SH1 north of Dunedin.
  • Further high rainfall, totalling at least 70 mm occurred in Northland on the 11th, followed by rainfall totalling about 100 mm in eastern Bay of Plenty, the Gisborne high country and coastal areas of southern Wairarapa on the 12th.

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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