"The flip side is rainfall projections and the soil on the east coast of Northland will be drier than normal which won't be good for agriculture. However, there are chances of heavy rainfall in the second half of November," Noll said.
Farmers, he said, should plan for a drier and warmer than normal weather as less rainfall and higher temperatures were predicted for December and January.
Ocean temperatures, he said, would likely increase between 2C and 4C but that wouldn't happen as early as next week.
"If you are taking advantage of the nice weather by going out fishing or swimming, make sure you put on the sunscreen as the UV (ultraviolet) index will be higher, even on cloudy days."
While tourism operators and holidaymakers are poised for a whale of a time, there will be anxious moments for farmers unless Northland receives intermittent rain.
Northland Rural Support Trust co-ordinator Julie Jonker said having gone through rough patches in summer months in the past - including three droughts in four summers earlier this decade - farmers would be doing everything necessary to ensure they got through the drier period.
The trust is having a meeting on December 3 to discuss plans should farmers got into difficulty.
"Farmers have been briefed about a potential El Nino this summer so they are making sure they have plenty of supplement, water supply and whether they need to de-stock," she said.
Northland tourism leader Jeroen Jongejans said most of the visitors the region received during summer months were domestic travellers, particularly Aucklanders, for whom weather played perhaps the most important role in their holiday plans.
"Tourism is still pretty seasonal up here and since we only get three to four months in the year to make money, it's important we get the right weather condition to meet the demands of our customers.
"If the prediction is for great weather, that will be fantastic. It's good that people are able to plan their summer travel now and we as tourism operators will be ready to deliver."
Jongejans said although tourists planned their holidays months in advance, they did not pre-book everything and clear skies and warm waters meant they'd spend more time in Northland.
Simon Egginton, owner of Tutukaka Surf, has already accepted bookings for next week from schools and said business should pick up as the weather started to get warm.
"Good weather and surf means more people coming out. There are a lot of school groups and tourists doing surf from now until January and let's hope this summer is as awesome as the last one."
NIWA said rainfall and river flows would be above normal while temperature and soil moisture above average throughout New Zealand between November and January.