The start to winter in Northland is likely to be warmer than average, judging from sizzling temperatures and a decent amount of rainfall over summer, WeatherWatch says.

Head analyst Philip Duncan said the prediction late last year of El Nino affecting Northland and the upper North Island has proven to be wrong. "In fact, Northland showed signs of La Nina, which meant a lot of easterlies, plenty of rain and high humidity. The prediction was for a drought but that didn't eventuate," he said.

On the flip side for Northland this winter, Mr Duncan said warmer than normal weather would increase chances of snow dusts on mountains due to moist air. A warmer than usual winter meant temperatures would be 1C or 2C higher, he said.

"A warmer climate does mean more chaotic weather and, while Northland is not likely to get colder than other places in New Zealand, one or two degrees warmer can make a lot of difference when you spread it out in winter," he said. "Most people would notice it in their power bills or the time to light fires in the evening will be delayed because of a slightly warmer day."

Advertisement

His comments followed the release of the seasonal climate outlook for April to June by the National Institute of Water and Atmospheric Research(NIWA) predicting above average temperatures for Northland. However, rainfall is predicted to be below average, and soil moisture and river flows near or below average.

NIWA scientists based their outlook on observations of atmospheric and sea conditions and output from global and local climate models. They said the presence of El Nino or La Nina conditions and sea surface temperatures around the country could be a useful indicator of likely overall climate conditions for a season. Kaitaia would likely be the hottest between April and June with the average temperature likely to be above 15C. Elsewhere around Northland, the average temperature will likely be above 14C.