Warmest August to date melts away winter that came early

Last month was the warmest August we have had in New Zealand since records began. Photo / Doug Sherring

This year's winter was a season of extremes, starting off early and extra frosty and ending unusually warm.

A summary shows the cold season arrived in May and was extra chilly this year, but also ended earlier with the warmest August we have had since records began.

Results released by the National Institute of Water & Atmospheric Research yesterday showed unusually high pressure over the country resulted in frosty temperatures beginning in May.

The average temperature for winter across the country was 8.3C, 0.2C higher than usual.

Niwa climate scientist Georgina Griffiths said the warmer winter was because of extreme swings in climate cycles.

"It was a bit of a topsy-turvy one at the start and then we had the turnaround - it was a big switch," she said. "It's not climate change per se, it's just climate patterns."

Temperatures in May were between 2C and 2.5C lower than average in many areas.

The coldest temperature recorded this year was in Middlemarch, Otago - minus 11.7C.

In contrast, last month brought an early end to the winter season with the warmest August in New Zealand since records began.

The hottest temperature was recorded in Timaru on August 25 - 22.2C.

Mrs Griffiths said an El Nino was affecting weather patterns.

She warned that if the El Nino intensified, many parts of the country could expect a dry summer which could cause droughts in some places.

"That El Nino has implications for New Zealand. That would mean a windy spring and an extra dry spring for parts of the north and eastern parts of both islands.

"That's a concern, but it's a 'watch this space' thing [because] at present, this El Nino is very weak. But we need to keep an eye on it."

It was a sunny winter for the north and west of the North Island, as well as the Clutha district and parts of Canterbury and Westland.

June was dominated by higher than normal pressures over the country, meaning more frosts and colder than normal temperatures everywhere.

Of the six main centres, Auckland was the warmest, Christchurch the coldest, Tauranga the wettest but also the sunniest and Dunedin the driest.