June 2007

Cold and wintry in the south, warmer in the north, sunny

• Temperature: Below average over much of the South Island, warmer in the north of the North Island
• Rainfall: Below normal in the northeast of the South Island, above normal in the south of the South Island
• Sunshine: Above average in many regions
• Wind: Rather windy at times over the south with strong westerlies and south westerlies

June 2007 was a wintry month in the South Island, especially in the south, with frequent bitterly cold southwesterlies, producing snowfall to low levels in Southland and Otago (as well as South Island high country passes) between the 7^th and 9^th and again from the 20^th to 24^th, with severe frosts following in many areas subsequently. Reefton, Hanmer Forest and the North Island’s Desert Road were affected by snowfall during the second event. However, June’s weather was more settled in the sheltered north-eastern areas of both islands.

The national average temperature was 7.9°C (0.6 °C below normal); a striking decrease of more than 4°C following the warmest May on record. Mean temperatures were at least 0.5 °C below average over much of the South Island. In contrast these were above average in parts of the north and east of the North Island. Rainfall was 75 percent (three quarters) or less of normal in some regions which received sheltering from the prevailing southwesterlies, such as Horowhenua, Kapiti, Wellington, Wairarapa, Marlborough, Nelson, and parts of Canterbury. However, exposed regions such as Southland and Otago were wetter than normal. Soil moisture deficits are still unusually high for the time of year in parts of Marlborough, Canterbury, north and Central Otagoo. June was also sunnier than normal over much of New Zealand.

Depressions (‘lows’) were much more frequent than normal southeast of the South Island, while anticyclones ('highs') were much more numerous south of Australia. This pattern produced more recurrent cold southwesterlies than usual over New Zealand, the strongest and most frequent for June since 2002. More days of with strong winds (gusts of 60 km/h or more) occurred over southern New Zealand. Three depressions developing off the eastern Australian seaboard moved southeast to affect New Zealand during the month (8^th -11^th June, 17^th -21^st June, and 27^th -30^th June).

Further Highlights

• The Southland and Otago snowfall event between the 7^th and 9^th, resulted in power outages, with 5–10 cm accumulating in many areas. About 10 cm accumulated in the same regions (including Queenstown and Dunedin hill suburbs) from the 20^th, where roads were icy and treacherous. Reefton, on the West Coast, had its largest snowfall (about 8 cm) since 1969.
• The highest temperature during June 2007 was 22.4 °C recorded at Rangiora on the 1^st.
• The lowest air temperature during the month was -10.8 °C recorded at Tara Hills, Omarama on the 22^nd.
• Two major rainfall events occurred in June: at Arthurs Pass, with 85 mm on the 1^st, and in Westland on the 29th with 130 – 170 mm.
• Wind gusts as high as 148 km/h were recorded from the west at Castlepoint on the 7^th, and at Taiaroa Head from the west on the 24^th. Gale force southerlies occurred in Cook Strait on the 26^th, with 5m swells, resulting in the cancellation of ferry crossings.
• Christchurch was the coldest, driest, and sunniest of the five main centres. Rainfall was below normal in Wellington and near normal elsewhere. Temperatures were above normal in Auckland and Hamilton, and below normal in the other main centres. Sunshine hours were above normal in all five main centres.

Temperature

Mean temperatures were at least 0.5 °C below average throughout much of the South Island, and at least 1.0 °C below average in Otago. However, they were at least 0.5 °C above average in parts of the north and east of the North Island, including Northland, Auckland, Bay of Plenty, Gisborne, and Hawke’s Bay.

Rainfall

Rainfall was 75 percent (three quarters) or less of normal in Horowhenua, Kapiti, Wellington, Wairarapa and Marlborough, and parts of Northland, Nelson, Canterbury, and Fiordland. In contrast, rainfall totals were almost 200 percent (twice) of normal in parts of Southland, and also above normal in South Otago, and parts of Hawke’s Bay and Westland.

Sunshine

June sunshine hours and/or solar radiation were more than 120 percent of normal in Kapiti, Canterbury, and east Otago, and at least 110 percent of normal in many other regions.

Full report

• Full details of the June 2007 Climate Summary

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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