People living in the north are in for a few sticky, tropical days and being told to expect some "seriously muggy nights".
MetService is warning in some regions temperatures will barely shift between daytime highs in the mid 20s and overnight lows as warm tropic-charged air washes over the top half of the country.
It says the North Island will experience some seriously muggy nights as fresh northerlies drag in sticky, warm air from the tropics.
Overnight temperatures on Tuesday will resemble daytime highs, possibly climbing to 20C in Hawke's Bay," said the forecaster in a Facebook post.