The worst of our scorching summer is probably over but don't put those cooling appliances away just yet.

A change from the humid northerlies to southwesterlies is bringing a cooler windflow to Northland and Niwa says it's a great weekend for outdoor activities.

Five places in Northland— Cape Reinga, Kaitaia, Kerikeri, Dargaville and Whangarei — broke the record for the hottest summer since records began, while Kaikohe recorded the second hottest.

Cape Reinga's highest temperature was 26.4C recorded on January 27, Kaitaia 28.7C on January 26 and 28, Kerikeri 29.5C on January 10, Dargaville 29.9C on February 12, Whangarei 30.2C on February 19 and Kaikohe 29.1C on January 24.


Niwa meteorologist Ben Noll said although Northland did not experience higher temperatures than places around the South Island, the region nonetheless felt its fair share of humidity.

Sea temperatures in Northland were 2C to 4C warmer than usual but in the South Island, they were between 4C and 6C— far above normal, he said.

"This represented some of the largest ocean temperature anomalies anywhere in the world over the last several months."

Mr Noll said a marine heatwave that began in November centred in the Tasman Sea meant the hot and humid air headed towards the South Island rather than the top of the North Island.

A warmer-than-average Tasman Sea, he said, was a signature of La Nina.

"It is associated with higher-than-normal air pressure over the region during late spring and early summer.

"These conditions prevent mixing of deeper, cooler sea water to the surface.

"Warm northeasterly winds also pushed warm water toward the country from the sub-tropics."

Mr Noll said humidity would remain low in Northland over the weekend but would start to increase around the first 10 days of March as the northerlies dragged hot air over the region.

"The worst of humidity is probably over for Northland but having said that, there will be periods of excessive heat and humidity in March and April but not as high as what we've experienced this summer."

He explained Northland, like the rest of New Zealand, had had a persistently hot summer but said the weather would blow hot and cold in the coming weeks.

Two ex tropical cyclones and one sub tropical storm passed through Northland in January and February that ensured humidity levels remained high, he said.

The hottest summer recorded in New Zealand was in 1934/35, when the temperature was 1.8C above average.