It's looking like a dry December across the country

A significant dry spell is developing across the country that could last into December.

WeatherWatch has reported an unusually long dry bout of weather is now setting in across New Zealand, after what has been an exceptionally wet year for many areas.

"The concern now for those who rely on water for business is that we may be going from one extreme to another."

Reliable long-range data sets show the country will be drier than average for the week ahead. Some computer models predict the high-pressure belt causing the dryness could not only last for the rest of November, but well into December.

Compared with November a year ago a number of regions are much drier.

WeatherWatch head forecaster Philip Duncan said looking at maps going out to November 30, "we can still see a huge belt of high pressure extending westwards from New Zealand".

"The best chance for rain makers is in the gaps between the highs, but with so much high pressure any rain bands may be short lived and narrow".

It's not all bad news, WeatherWatch assures. Despite the dry forecast the large high next week is expected to produce more daytime heat showers.

Earlier this week these gave Waikato, Auckland and Northland farmers some relief.

But Eastern parts of both islands are now drier than average, and with a drier than average weather forecast it means summer will be kicking off on a dry, warm note.

"This dry spell is forming fast and looks significant when you take into account how much more high pressure is yet to come in," said Duncan.

The sub-tropics are also quite active, but until the protective layer of high pressure shifts away these rainmakers "will be stuck in a rut" pushing down just to the northeast of New Zealand.

Duncan said the rainbands are near, just needed are the highs to change shape to allow them in.

Fiordland is one of the wettest places on earth, but for the next two weeks Milford Sound will have mostly to completely dry weather with temperatures pushing well into the mid-20s this weekend, WeatherWatch predicts.

The weak cool front in the South Island today and the sub-tropical low approaching the upper North Island tomorrow are both expected to produce very little moisture for New Zealand.