October 2002

Friday, 1 November 2002
The coldest October since 1982, with below average temperatures almost everywhere
Extremely sunny with below average rainfall in many regions
Wet in the east north of Gisborne and in the far south
October received more than the usual number of cold snaps, keeping temperatures well below normal in many areas. Ground frosts occurred with twice their normal frequency in inland parts of Bay of Plenty and Canterbury.

Friday, 1 November 2002

The coldest October since 1982, with below average temperatures almost everywhere Extremely sunny with below average rainfall in many regions Wet in the east north of Gisborne and in the far south

October received more than the usual number of cold snaps, keeping temperatures well below normal in many areas. Ground frosts occurred with twice their normal frequency in inland parts of Bay of Plenty and Canterbury. The month was also exceptionally sunny compared to average, with many locations, throughout New Zealand, experiencing one of their sunniest October’s on record.

The normal spring warming was absent in October, due to the frequent southwesterlies and also frequent clear cold nights. The national average temperature of 11.0°C (1.1°C below normal) was the same as that of September 2002, and the lowest for October since 1982. Mean temperatures were at least 0.5 to 1.5°C below average throughout much of New Zealand. It was particularly cold, with temperatures more than 2.0°C below normal in parts of King Country, and inland Wanganui. In Canterbury, this was in significant contrast to September, which was very much warmer than normal.

Rainfall was below average throughout much of the North Island, the northern South Island, and parts of Central Otago. In central Marlborough rainfall was below average for the fourth consecutive month, with totals being 50 percent (half) or less of average. Rainfall was also 50 percent (half) or less than average in Bay of Plenty, and parts of the southern North Island. As a result, significant soil moisture deficits persisted in central Marlborough and now exist in northern and Central Otago and inland South Canterbury. In contrast, it was unsettled with above average rainfall in the east (north of Gisborne) and in coastal Southland.

October’s climate pattern was dominated by well below average pressures east of the Chatham Islands, producing more frequent cold southerlies over the eastern South Island and southwesterlies over the North Island.

Below average temperatures almost everywhere

Mean temperatures were at least 0.5°C below normal throughout much of New Zealand. They were at least 1.0°C below normal in the central and western North Island, south of Auckland and north of Wellington, including Gisborne, and in Canterbury, Otago and Westland. It was particularly cold, with temperatures between 1.5 and 2.5°C below normal in King Country and Wanganui.

Near or record low mean October temperatures were recorded at:

Location Mean temperature Departure (°C) Records began Comments
Henderson, Auckland 13.1 –1.9 1986 2nd lowest
Paeroa 12.2 –1.8 1947 2nd equal lowest
Rotorua Airport 10.4 –1.7 1964 Equal lowest
Taupo Airport 9.6 –1.4 1976 2nd lowest
Taumarunui 10.5 –2.3 1947 2nd lowest
Chateau, Ruapehu 4.5 –2.1 1932 3rd equal lowest
Christchurch Airport 9.9 –2.0 1953 3rd lowest
Ettrick 9.5 –1.8 1985 Lowest
Gore 8.2 –1.7 1971 Lowest

Overnight minima were particularly low, being about 1.5°C below normal in many locations. Near or record low October mean daily minimum temperatures were recorded at:

Location Mean daily minimum temperature Departure (°C) Records began Comments
Henderson, Auckland 7.2 –3.1 1986 Lowest
Paeroa 6.6 –2.2 1947 Well below average
Whakatane Airport 5.6 –2.6 1975 2nd lowest
Rotorua Airport 5.1 –2.5 1964 Lowest
Taupo Airport 4.2 –2.1 1976 2nd equal lowest
Taumarunui 4.7 –2.7 1947 Lowest
Whakatu 5.9 –2.2 1983 2nd lowest
Blenheim Airport 4.3 –2.4 1941 Lowest
Hanmer Forest 1.7 –2.5 1906 3rd lowest
Christchurch Airport 3.5 –2.9 1953 Lowest
Timaru Airport 2.8 –2.1 1962 2nd lowest

Below average rainfall in many regions Wet in the east north of Gisborne and in the far south

Rainfall was 75 percent or less of average throughout much of the North Island, the northern South Island, and parts of Central Otago. Rainfall was below average for the fourth consecutive month in central Marlborough, October totals being 50 percent or less of average. Rainfall was also 50 percent or less of average in Bay of Plenty, and parts of the southern North Island. Near record low October rainfall was recorded at:

Location October rainfall (mm) Percentage of normal Records began Comments
Te Puke 57 42 1973 3rd lowest
Palliser 10 15 1987 3rd equal lowest
Wellington Airport 22 27 1960 3rdlowest

The month was unsettled with rainfall totals at least 120 percent of average in the east, north of Gisborne, and in coastal Southland.

Near record high October rainfall was recorded at:

Location October rainfall (mm) Percentage of normal Records began Comments
Invercargill Airport 163 180 1939 2nd highest
Chatham Islands 116 207 1951 3rd highest

Extremely sunny in most areas

Sunshine and solar radiation totals were 120 percent or more of average and exceptionally high for October at many locations throughout New Zealand.

Near or record high October sunshine was recorded at:

Location October sunshine (hours) Percentage of normal Records began Comments
Kaitaia 242 130 1951 Highest
Auckland 255 134 1909 Highest
Taumarunui *206 139 1947 2nd highest
New Plymouth 254 134 1915 Highest
Paraparaumu Airport 257 143 1953 Highest
Wellington, Kelburn 260 133 1928 Highest
Hokitika Airport 227 141 1964 2nd highest
Nelson Airport 283 131 1948 2nd highest
Blenheim 282 125   3rd highest
Christchurch 272 133 1930 Highest

* to 9 a.m. on 31 October

Record high October solar radiation was recorded at:

Location October solar radiation, mean daily (MJ/m2) Percentage of normal Records began Comments
Whitianga Airport 20.5 126 1991 Highest
Te Puke 18.9 121 1987 Highest

Highlights

Extreme temperatures

  • The lowest air temperature for the month was –7.4°C, recorded at The Chateau, Ruapheu on the 5th. The only lower October air temperature on record there is –8.3°C in 1945.
  • The highest air temperature for the month was 26.1°C, recorded at Hanmer Forest on the 24th. The highest October air temperature on record at Hanmer Forest is 28.3°C.

Other extremely low October minimum air temperatures were recorded at:

Location Minimum air temperature Date Records began Comments
Lumsden –4.1 4 Oct 1987 Lowest
Taupo Airport –5.1 5 Oct 1976 Lowest
Motu –5.8 5 Oct 1991 Lowest
Waiouru Military Camp –6.3 5 Oct 1966 Lowest
Culverden –5.0 15 Oct 1983 Lowest
Arthur’s Pass –5.0 21 Oct 1978 Equal lowest

Significant hailstorm

  • Thunderstorms with large hail occurred in Canterbury on the 27th. Hailstones, some the size of golf balls, occurred in the Hornby area, damaging numerous strawberry plants. Other damages reported were denting of vehicles, and broken windows. Significant surface flooding resulted in Hornby shops after the event.

Tornados

  • A tornado occurred at Taitapu, near Lincoln, southeast of Christchurch on the 28th, damaging trees in the area. Another tornado was sighted in Auckland on the 29th.

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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