Long hot summer bids warm farewell

A swimmer enjoys the warm autumn weather at Parnell Baths. Photo / Natalie Slade

The North Island's extended summer will last at least another week, with most regions expected to bask in low-20C temperatures beyond the weekend.

Summer has begun slipping away, say forecasters, but only very gradually.

Niwa climate scientist Georgina Griffiths said a record-breaking February had been followed by a warmer-than-usual March, with Auckland and Northland regularly experiencing low to mid-20C temperatures.

After three months of steady heating, ocean temperatures remain warm - about 22C along Auckland's coastline.

MetService weather ambassador Bob McDavitt said the warm conditions would continue, with mostly fine weather predicted until at least Sunday.

Tomorrow will see some showers in the North Island, but the weekend will be clear and sunny.

The earthquake memorial service in Christchurch tomorrow will take place between two southerly fronts and conditions are expected to be mostly fine, with temperatures of about 20C.

Mrs Griffiths said La Nina's warmer waters were slowly retreating from our shores, and the Southern Ocean was beginning to play more of a part in our weather patterns.

Auckland felt its first noticeable southerly on March 6, foreshadowing the chillier winds and temperatures.

The first signs of snow arrived at Mt Taranaki last week, and many South Island spots dropped into single-digit temperatures.

Mr McDavitt said fronts were creeping further up the country, with more intensity. "The strong winds - Roaring Forties - will become more influential, and we'll notice that over the next six weeks. We've had a bit of snow in the North Island, and we'll get more and more of the southerlies."

Niwa has predicted a mild autumn, with above average temperatures from March until May and more rainfall than usual.

It is too early to forecast how cold New Zealand's winter will be. But forecasters predict it will be a neutral season, with no influence from La Nina or El Nino.

The summer has been affected by the strongest La Nina pattern in 30 years, which has caused numerous heat records, as well as flooding in the North and South Islands.