If you thought it's been humid already, it may be about to get stickier.

WeatherWatch.co.nz reported a tropical cyclone may briefly develop over the Coral Sea in the next 24 hours, then weaken and head towards New Zealand around Thursday.

"Think of a tropical storm as a candy floss machine - the centre of the low is the stick and as it spins in the tropics humid, hot, air attaches itself to the low, wrapping all around it," WeatherWatch forecaster Philip Duncan said.

"When the low tracks south it takes all this humid weather with it and can transfer tropical weather to New Zealand."

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This could happen on Thursday and Friday, before a southerly behind the low cleared things up briefly, Duncan said.

But New Zealand may be about to deal with a double dose of tropical trouble.

It was possible that the first week of February could see another tropical storm to our north.

"The second one is too far out to lock in but models are suggesting it could impact New Zealand around Waitangi Day - although it's still a very long way out and could miss us, but may bring dangerous beach conditions if it does eventuate and track nearby."

Duncan said the beginning of February opened up the doors to the tropics north of New Zealand - and could mean very heavy rain in both islands along with heat and humidity, especially for the North Island.

"At this stage neither low is forecast to hit New Zealand as a storm - but it's just highlighting the fact that the tropics are now becoming incredibly active and all it takes for New Zealand to be impacted by more hot and humid weather is for high pressure to leave our area and allow tropical lows to drift south towards us."

A simulated model of remnants of a tropical low reaching New Zealand. Image / Weathermap.co.nz/WeatherWatch
A simulated model of remnants of a tropical low reaching New Zealand. Image / Weathermap.co.nz/WeatherWatch

It came at the end of what climatologists predict could be our hottest January on the books - and a month that's been insufferably sticky across the North Island.

"Bad hair days, clammy hands - for anyone who goes out there, it's just been oppressive," said Niwa meteorologist Ben Noll, who put the clammy climate down to a persisting flow of warm air from the subtropics.

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"If you've been in a place that doesn't have air conditioning, you will have been sweating."

And it hasn't just been us.

Fans of baking might have noticed how pavlovas, ordinarily a Kiwi summer classic, have been dripping sugar amid air packed with moisture.

"We call that beading," Kiwi cooking personality Allyson Gofton said.

But beading - when the cakes leaked droplets of sugar from the inside - tended to be more of a problem when people tried to store pavlovas for a day or two after baking.

"We also tell people if they're going to bake a pav in summer, do it in the cool of evening, or in the morning."

The relentless mugginess had been a hot topic among city hairdressers having to negotiate extra frizz, said Kurtis Counsell, of Auckland salon Hair Nerd.

"We are getting a lot of people with frizzy hair asking what they can do about it but it's pretty unavoidable," Counsell said.

"You could sell them anything with anti-frizz or anti-humidity, but when it's as humid as it has been, it really isn't going to do that much."

The messy look was caused by the extra amounts of hydrogen hanging in the air, which formed bonds between the protein and water molecules in hair, making it curlier and frizzier.

A long range map for Waitangi Day suggests a tropical storm will be just north of New Zealand. This isn't locked in and may change. Image / Weathermap.co.nz
A long range map for Waitangi Day suggests a tropical storm will be just north of New Zealand. This isn't locked in and may change. Image / Weathermap.co.nz

Incredibly, our bodies could adapt after just a few weeks of humid weather, by better balancing our fluids and sweating more efficiently. But until that occurred, we found it harder to deal with mugginess than we otherwise might with dry heat.

When temperatures rise, humans shed heat through the evaporation of sweat from our skin, which occurs smoothly when there's little moisture in the air.

But humidity compromised our ability to do so - which was why being in a rainforest was much more stressful on our physiology than a desert would be.

Drinking plenty of water was a good antidote - and not just for that quick hit of cool relief.

Image / The Weather Company
Image / The Weather Company

"When you sweat, it's basically just filtered blood," University of Auckland thermoregulation expert Dr Nicholas Gant said.

"And it's the plasma of your blood that goes up through your sweat ducts, so you are literally losing fluid that you would have been using for something else.

"It's why, if you do have a high sweat rate, it's really important to drink appropriately, especially during exercise, when you really need all of the blood you've got."

It was still tough to acclimatise to hot nights - especially for those who didn't have air conditioning, or even a good fan handy.

In Auckland over January, the average overnight temperature is 15.7C.

It's regularly been higher than that this month, and next week night-time temperatures are tipped to reach over 20C.

Noll, too, didn't see respite from the humid hell any time soon either.

"February is shaping up to be a very active month, so it's something that looks like it's going to continue."