Weather: Muggy nights to continue for weeks in Northland

Nine-year-old Dredyn Abraham beats the heat with a jump into the Waipu River. Photo / John Stone

You could be forgiven for thinking you were in the tropics with the warm temperatures and high humidity enveloping Northland.

And weather experts say muggy nights leading to uncomfortable sleeps are not going anywhere for the next month.

At 2pm yesterday the hottest place in Northland was Whau Valley where the mercury soared to 33C, followed by Whangarei Airport on 27C as well as Kaikohe on 27C.

For those visiting Cape Reinga about the same time the temperature was a balmy 23C but the humidity reading was 81 per cent. Kaikohe was also steaming with 71 per cent humidity and Whangarei on 61 per cent.

The term humidity generally refers to the amount of this water vapour in the atmosphere.

MetService meteorologist John Law said the dew point, which is a measure of humidity, was because of the sub-tropical northerly air flow and warm seas that had combined and wrapped itself around New Zealand. It is deemed uncomfortable when it goes higher than 18C.

So overnight temperatures over the next week will remain around 20C, meaning steamy sleeping conditions. Mr Law said the general weather pattern causing the uncomfortably, sticky nights was set to be with us through February at least.

"It's shaping up to be a very hot month and we will have to start looking at some [temperature] records I think. And it's been equally as hot at night," Mr Law said.

He said daytime temperatures in Northland were well above the January average of 24C and well above the nighttime average of 15-16C for the month.

"You guys in Northland are used to having a warm January and tropical temperatures but this has been particularly warm for a long period."

Part of the reason for the above-average warm weather was the fact that any southerlies to hit the country were on the back of the subtropical low, so had not brought in cool, dry air from Antarctica, rather they had just recycled the warm air from ahead of the low.

But if it's too warm on land take advantage of the ocean which has heated up to between 21C and 22C off Northland's coastline, which was also above average for this time of year.

Last year Whangarei had its warmest day since records began half a century ago with 31.8C on February 13, which was recorded at the airport. However, the temperature is at least four degrees higher inland.

Weather for Northland's Anniversary weekend looks good with Saturday and Sunday mainly fine with southeasterly winds and a high of 27C. Monday's temperature dips slightly to 26C while showers develop on Tuesday with rain on the radar for Wednesday, Thursday and Friday. But a week in weather is a long time so things could change.