June one of hottest ever - despite cold nights

Above average rainfall that has filled Auckland's dams is one of a string of weather extremes that included the hottest-ever February and a late-arriving winter. Photo / Brett Phibbs

The warmest May on record was nearly followed by the hottest June, until a cold snap this week finally started the winter chill.

Until Tuesday, June temperatures were 1.8C warmer than usual throughout New Zealand, a temperature shared with June 2003.

Rainfall was also well above average for Auckland and parts of the North Island.

Freezing winds which arrived from the Southern Ocean this week have lowered the average temperature, but the month was still 1.6C warmer than normal, according to climate scientist Jim Salinger.

Dr Salinger said New Zealand's average temperature in June was 9.9C. "So it can be described as 0.5C shy of the warmest on record ... no wonder the snow was very late in coming."

National Institute of Water and Atmospheric Research (Niwa) climate scientist Brett Mullan said the mild June was the last trace of one of the strongest La Nina cycles the country has seen.

The wet month has also produced high river levels. Auckland's Watercare provider said the region's lake levels, fed by dams in the Hunua and Waitakere ranges, were at 100 per cent - above average for this time of year.

For the first 28 days of June, Auckland was 2C warmer than usual during the day and 2.3C warmer at night. The Mangere weather station recorded 160mm of rainfall this month, compared to an average of 139mm.

The hottest spot in the country was believed to be Kaikohe, which reached 26.3C.

At the other end of the thermometer, Lumsden and Clyde in the south of the South Island both dropped to 4.8C as winds from the Antarctic swept the country this week.

Coastal Otago was the only region to have a slightly cooler than usual June.

The warm start to winter delayed the opening of skifields, and led to lower lake inflows than expected.

This year has already brought Auckland's hottest February and the country's warmest May on record.

The mild weather looks likely to continue. Niwa's seasonal climate summary predicts temperatures near or above average for most of the country from July to September.

JUNE (FIRST 28 DAYS)
* New Zealand - 1.8C warmer than normal
* Warmest spot - Kaikohe: 26.3C.
* Coldest spot - Lumsden, Clyde: -4.8C.
* Auckland - 2C higher than normal, with 144-160mm (above average) rainfall.

2011: YEAR OF HEAT EXTREMES
* February - warmest on record for Auckland, Nelson, warmest day in Timaru in 125 years (41.4C).
* May - warmest on record for New Zealand, 2.5C above normal.
* June - New Zealand at least 1.5C higher than normal.