Some Advocate readers have reported temperatures reaching into the 30s at their properties.
Last week was not the hottest this summer though - the week of December 17-22 has so far taken that crown, when the official high hit 28C.
Overnight lows for this year have been between 12C and 17C in Whangarei, and 13C and 18C in Kaitaia.
"I guess in the Winterless North, that's pretty cool.
"In somewhere like Wellington, it would be considered mild," Mr Little said.
The warm spell comes after a damp December, with some steady rain, thunder and lightning, wind gusts and some road surface flooding in the week before Christmas.
The week's unseasonable fare had come towards the end of a warmer, wetter year than normal, characterised by back-to-back extremes. Conditions swung from extremely dry at the start of the year to record wet during winter and into spring.