National Climate Summary – December 2005

National Climate Summary - December 2005

Rainfall: Wet in the north and west of the North Island, especially Northland, western Bay of Plenty, and Wanganui; below normal in Hawke's Bay and Marlborough

Soil moisture: Significant deficits in eastern regions from Hawke's Bay to Otago, as well as Kapiti, Wellington and Nelson

Temperatures: Well above average in most places, third warmest December on record

Sunshine: Normal or below normal throughout New Zealand

Contrasts in rainfall occurred in December, with extremely high totals in northern parts of Northland, western Bay of Plenty, and Wanganui (highest in 115 years of record), and comparatively low totals in parts of Hawke's Bay and coastal Marlborough. Significant soil moisture deficits occurred in eastern regions from Hawke's Bay to Otago, as well as Kapiti, Wellington and Nelson, being severe in parts of Marlborough and Central Otago. Temperatures were remarkably high throughout the nation. The national average temperature was 17.5 ¢XC, 1.9 ¢XC above average. This was the warmest December in 71 years (18.5 ¢XC in 1934), and third warmest since reliable records commenced in the mid 1860s (December 1872 had 17.8 ¢XC). Sunshine hours were normal or below normal throughout New Zealand. December mean sea level pressures were well below average in the Australian Bight, extending troughs of low pressure ("lows') toward New Zealand. This pattern produced more frequent warm northerlies over the North Island and more northeasterly airflow than average over the South Island.

Other Highlights:

The highest temperatures during December 2005 were 31.7 ¢XC recorded at Darfield on the 30th, and 31.5 ¢XC at Napier Airport on the 31st. The lowest temperature for the month was 1.5 ¢XC at Chateau Ruapehu on the 25th.

Periods of high rainfall affected parts of the North Island from Northland to Wanganui between the 13th and 17th.

The highest wind gust for the month was 137 km/h from the northwest, at Castlepoint on the 4th.

Damaging hailstorms occurred in Southland on both the 5th and 15th.

Damaging tornadoes, or tornado-like winds occurred in Rotorua on the 6th, and Southland on the 15th.

Lightning strikes left many people temporarily without power in Taranaki on the 6th.

Of the four main centres Christchurch was the driest, and Dunedin wettest.

Rainfall was above average in Dunedin, near average in Auckland and Wellington, and below average in Christchurch. Temperatures were above average in all four main centres. Sunshine hours were near average in Auckland and Wellington, and below average in Christchurch and Dunedin.

Rainfall:

Rainfall was least 300 percent (triple) of normal in northern parts of Northland, and at least 200 percent (twice) of normal in western Bay of Plenty, and Wanganui. It was also wetter than average in Thames, inland Bay of Plenty, Waikato, King Country, southern Taranaki, Manawatu, coastal parts of south Canterbury, and western and inland Southland. Rainfall was less than 50 percent of normal in parts of Hawke's Bay, and also below normal in Marlborough.

Temperature: Mean temperatures were at least 1.5 ¢XC above average throughout much of New Zealand. They were 3.0 ¢XC or more above average in parts of Otago, and Southland, and at least 2.0 ¢XC above average in eastern Bay of Plenty, the west of the North Island from Manawatu to Wellington, and most of the South Island.

Sunshine: Sunshine hours were 80 percent or less of normal in Waikato, King Country, Nelson, and coastal north Canterbury, and less than 90 percent of normal in Taranaki, inland Canterbury, and Otago. They were near normal elsewhere.

WET IN THE NORTH AND WEST OF THE NORTH ISLAND, ESPECIALLY NORTHLAND, WESTERN BAY OF PLENTY AND WANGANUI

Rainfall was least 300 percent (triple) of normal in northern parts of Northland, and at least 200 percent (twice) of normal in western Bay of Plenty, and Wanganui. It was also wetter than average, with totals at least 125 percent (one and a quarter) of normal in Thames, inland Bay of Plenty, Waikato, King Country, southern Taranaki, Manawatu, coastal parts of south Canterbury, and western and inland Southland.

Near or record high December rainfall was recorded at:

Location December

Rainfall (mm) Percentage

of normal Year

records began Comments

Cape Reinga 177 306 1919 Highest

Tauranga Airport 189 218 1898 Well above average

Lower Retaruke 228 177 1966 3rd highest

Wanganui 196 279 1890 Highest

Ranfurly 116 213 1975 3rd highest

Lumsden 190 208 1986 2nd highest

BELOW NORMAL RAINFALL IN HAWKE'S BAY AND MARLBOROUGH

Rainfall was less than 50 percent of normal in parts of Hawke's Bay, and less than 75 percent of normal rainfall in Marlborough.

ONE OF THE WARMEST DECEMBERS ON RECORD

TEMPERATURES WELL ABOVE AVERAGE IN MOST REGIONS

Mean temperatures were at least 1.5 ¢XC above average throughout much of New Zealand. However, they were 3.0 ¢XC or more above average in parts of Otago, and Southland, and at least 2.0 ¢XC above average in eastern Bay of Plenty, the west of the North Island from Manawatu to Wellington, and most of the South Island. Mean daily minima were 2.5 to 3.0 ¢XC or more above average throughout much of the South Island.

Near or record high December mean air temperatures were recorded at:

Location Mean temperature Departure from average (¢XC) Records

Began Comments

Whangarei Airport 19.8 +1.6 1967 Highest

Auckland, Henderson 19.4 +1.3 1985 Equal highest

Tauranga Airport 19.2 +1.7 1913 Highest

Whakatane Airport 19.1 +2.1 1974 Highest

Motu 16.2 +2.0 1990 Highest

Auckland Airport 19.6 +1.4 1962 Highest

Pukekohe 18.5 +1.5 1970 3rd highest

Hamilton Airport 18.0 +1.5 1970 Well above average

New Plymouth Airport 17.7 +1.5 1944 Equal highest

Mt Ruapehu, Chateau 12.0 +1.5 1932 Well above average

East Taratahi 18.1 +2.9 1972 2nd highest

Mahia 18.4 +1.3 1990 Highest

Paraparaumu Airport 17.6 +1.7 1953 Equal highest

Palmerston North EWS 18.3 +2.0 1928 2nd highest

Levin 18.0 +2.1 1895 Equal highest

Wellington, Kelburn 17.4 +2.0 1928 2nd highest

Wellington Airport 18.1 +1.7 1962 Equal highest

Wallaceville 17.7 +2.2 1939 Highest

Stratford 15.8 +1.5 1960 Well above average

Wanganui, Spriggens Park 18.8 +2.0 1937 Equal highest

Farewell Spit 18.4 +2.5 1972 Highest

Westport Airport 16.9 +1.9 1937 2nd highest

Lake Rotoiti 15.2 +2.3 1965 Equal 2nd highest

Hokitika Airport 16.7 +2.4 1963 Highest

Franz Josef 16.1 +2.6 1982 Highest

Milford Sound 16.3 +2.8 1934 2nd highest

Puysegur Point 15.8 +3.2 1978 Highest

Stephens Island 16.8 +2.3 1973 Highest

Motueka, Riwaka 18.6 +2.5 1956 Highest

Nelson Airport 18.8 +2.6 1943 Highest

Blenheim Research 18.4 +1.7 1985 2nd highest

Blenheim Airport 18.6 +2.3 1941 Equal highest

Arthurs Pass 13.7 +2.5 1978 Highest

Winchmore 16.9 +2.1 1949 2nd highest

Rangiora 17.0 +1.6 1965 Well above average

Christchurch Airport 17.2 +1.5 1953 Well above average

Lincoln 17.2 +1.9 1881 Well above average

Timaru Airport 16.2 +1.7 1962 3rd highest

Tara Hills 16.9 +2.5 1949 Equal highest

Wanaka Airport 18.3 +2.5 1992 Highest

Dunedin Airport 16.7 +2.9 1962 Highest

Dunedin, Musselburgh 15.5 +1.6 1947 2nd highest

Manapouri Airport 15.8 +2.9 1991 Highest

Queenstown 17.8 +2.7 1871 3rd highest

Lauder 17.3 +2.9 1981 Highest

Clyde 18.6 +2.8 1983 Highest

Ettrick 17.8 +2.3 1986 Highest

Gore 16.1 +2.6 1987 Highest

Invercargill Airport 16.4 +3.4 1948 Highest

Tiwai Point 16.3 +2.9 1970 Highest

Campbell Island 10.9 +2.1 1941 Highest

AVERAGE OR BELOW AVERAGE SUNSHINE THROUGHOUT MUCH OF NEW ZEALAND

Sunshine hours were 80 percent or less of normal in Waikato, King Country, Nelson, and coastal north Canterbury, and less than 90 percent of normal in Taranaki, inland Canterbury, and Otago. They were near normal elsewhere.

Near record December sunshine hours were recorded at:

Location December

sunshine

(hours) Percentage

of normal Year

Records began Comments

Taumarunui 122a 66 1947 2nd lowest

Christchurch Airport 151b 68 1949 2nd lowest

a missing 22 Dec. b missing 31 Dec.

DECEMBER'S CLIMATE IN THE FOUR MAIN CENTRES

Of the four main centres Christchurch was the driest, and Dunedin wettest. Rainfall was above average in Dunedin, near average in Auckland and Wellington, and below average in Christchurch. Temperatures were above average in all four main centres, especially Wellington. Sunshine hours were near average in Auckland, and Wellington, and below average in Christchurch and Dunedin.

Location Dec.

Mean

Temp.

(¢XC) Dep.

from normal

(¢XC) Dec.

rainfall

(mm) % of

normal Dec.

Sunshine

(hours) % of

Normal

Auckland 19.1 +1.0 Above average 96 106 Near average 220 105 Near average

Wellington 17.4 +2.0 2nd highest 76 89 Near average 233 103 Near average

Christchurch 17.5 +1.4 Above average 36 73 Below average 151 68 Well below average

Dunedin 15.5

+1.6 2nd highest 115 140 Above average 145 86 Below average

a Auckland Airport

HIGHLIGHTS AND EXTREME EVENTS

- Temperature

The highest temperatures during December 2005 were 31.7 ¢XC recorded at Darfield on the 30th, and 31.5 ¢XC at Napier Airport on the 31st. The lowest temperature for the month was 1.5 ¢XC at Chateau Ruapehu on the 25th.

- Rainfall

Rainfall totalled over 100 mm at Cape Reinga on the 13th, and over 50 mm in parts of Northland, Thames, Bay of Plenty, and Taranaki from the 15-17th. Torrential rainfall occurred in Wanganui during the afternoon on the 13th totalling 20 mm in 20 minutes.

- The highest wind gust for the month was 137 km/h from the northwest, at Castlepoint on the 4th.

- Hail, thunderstorms, and tornadoes

Marble-sized hailstones occurred during thunderstorms in Waimatuku, Southland on the 5th, after which four tornadoes were sighted, with some damage to property.

Sudden and brief tornado-like winds occurred in Rotorua on the 6th damaging property. Frequency lightning strikes occurred in Taranaki on the same day, leaving over 3000 people temporarily without power. Tornado-like winds and intense hail also occurred at Heddon, Southland on the 15th, felling trees and destroying crops.

ENDS

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