Mean air temperature records were set in Cape Reinga (20.3C, up 1.3C), in Kaitaia (21.6C, up 2.2C), and Kerikeri (21.1C, up 1.9C).
Northland Rural Support Trust co-ordinator Julie Jonker said rain during the month, particularly along the west coast in Dargaville, Ruawai, and Te Kopuru, was much needed.
"Northland has been very lucky this summer and the rain we've had has resulted in amazing grass growth and pasture cover so farmers are quite relaxed about the feed situation.
"But they'll prefer the rain to stop once we get to winter as we've had a wet winter last year," she said.
Northland tourism leader Jeroen Jongejans said although the region avoided the worst weather experienced in other parts of New Zealand, it lost five significant days.
"This time of the year the tourism industry needs to make up for winter so the lost days are significant. You make more in one day in summer than you do in a month in winter.
"It's been a mixed bag in January. Land activities have been good, visitor numbers were up but the ability to maximise opportunities in the ocean has neither been the worst ever nor the best," he said.
Jongejans said some sectors, particularly the farming and the hospitality industry, have done very well in January.
Niwa's climate summary shows Kaikohe recorded its strongest-ever January wind gust at 89km/h, and Kaitaia its third-strongest at 93km/h.
There were 21 new record daily maximum temperatures in New Zealand, including at Cape Reinga (26.4 degrees), while Kaikohe recorded its fourth-highest maximum (29.1 degrees).
Niwa's expectations for Northland over the next three months are higher than average temperatures, rainfall, soil moisture and river flows.