Hot in the city! No relief in sight for sleepless Aucklanders struggling through muggy January nights

If you think hot summer nights in Auckland this New Year have been a little more sultry than soothing, you're not imagining it.

Above-average overnight summer temperatures made worse by unrelenting humidity have Aucklanders tossing and turning through unusually muggy nights so far in 2018.  

Every day this January, the lowest daily temperature has been noticeably above the historical average overnight Auckland January temperature of 15.7 degrees.

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The average lowest daily temperature for January 2018 has been has been 17.9 degrees.

And MetService meteorologist Tom Adams says this isn't even the total explanation.

"There's two things at play, temperature and humidity, and just giving the temperatures doesn't give the whole story," Mr Adams says.

"If we had the same temperatures on a summer night with hot dry air it would be much more comfortable.

"It's the difference between walking off a plane at Singapore Airport, compared to walking through a desert. 

"It is going to feel warmer this January because of frequent humid air masses over the country of tropical origin.

"What we haven't had at all is colder southerlies which bring cold dry air of a polar origin."

The daily lowest temperature nearly always comes overnight, so it means Auckland has been at least a couple of degrees above average each night this January than usual.

And it's not forecast to get any better over the next 10 days, with the average overnight temperature set for 18.1 degrees. Yikes.