It's the last day of summer today but the hot, sticky air left over from former Cyclone Winston could continue to hang around for much of the week and keep the autumn weather at bay.
Northland, Auckland, Coromandel, the East Cape and Bay of Plenty have been experiencing unusually humid weather, coupled with temperatures in the mid-high 20s.
"Anytime we put out a story which says somewhere in the upper North Island feels like it's in the 30s, people who live on the east coast of both islands say this is Auckland and Hamilton and they're fake 30s," said WeatherWatch head weather analyst Philip Duncan. "But actually it's not.
"Because those other regions don't really get the high temperatures with the high humidity and that's the difference.
"When it's this humid your sweat doesn't get absorbed by the air so it stays on you all sticky and yuck and you can't get rid of that dampness."
Mr Duncan said a high pushing in from the Tasman was threatening to push the muggy weather offshore.
However, the "lively" air from ex-cyclone Winston would push back and may not budge from the top of the country.
"When you have a windy, warm day followed by a windy, colder day, the wind swings to the southwest which is a tell-tale sign that we're floating towards autumn, right on cue.
"But the nation's broken into three sections," he said.
"You've got the whole South Island and the lower North Island under a little bit more of a spring-like pattern, although Wellingtonians won't agree with that because it's been very summer-like lately.
"Then in the central North Island, up to about Waikato or Auckland, you're getting this tropical rain," Mr Duncan said.
"North of that and you're in the tropical air but it's not necessarily rain, which will be stuck in that for a few more days at least."
By Tuesday, there would be a "fuzzy grey line" near Auckland separating the humid weather from a slightly cooler change pushed in by the Tasman high.
Which weather system would prevail was not yet clear.
The week ahead
Dunedin - A cooler start to the week is forecast with temperatures picking up to the mid 20s as the week progresses.
Whangarei - The north is forecast to have more cloud, hot weather all week.
Auckland - The Queen City is in for more hot, muggy weather with temperatures in the mid-high 20s and several chances of rain.
Wellington - Mostly clear skies ahead for the capital, with temperatures forecast to be in the low-mid 20s.
Christchurch - A cooler start to the week with temperatures in the late teens, forecast to climb to 26C on Thursday and 30C on Sunday.
