It is officially summer, but you wouldn't guess it given the weather that's expected over the next week or so.

Dreary days, strong gusty winds and patches of cloud have been predicted for the coming week.

MetService has even issued a Severe Weather Watch warning for a burst of heavy rain northwest of Nelson from this morning through to early afternoon.

Weather Watch chief analyst Philip Duncan said the country was in for "a very, very wet week".


"Basically we've got the subtropics coming down to visit us this week, so it's going to be warm, wet and humid in the North Island and probably a mixture of cloudy and wet days in the south."

A front forming over the Tasman Sea yesterday will bring a band of rain on to Northland and the west of the South Island in the evening.

The rain was to cross most of the South Island today, then stall over central and northern New Zealand.

As a result, a prolonged period of rain is likely for parts of the North Island and upper South Island over the next few days, the MetService said.

Rain is expected to continue until at least next Friday.

Mr Duncan said this weather was typical during a La Nina summer which New Zealand is experiencing at the moment.

La Nina summers are usually quite warm with average rainfall.

Mr Duncan said there had recently been a number of highs which sat just north of New Zealand which kept the subtropical weather at bay and the skies clear.


But in the past few weeks, those highs had moved further south, leaving a vacuum over the country where lows could form. He said it would probably be a few weeks before the weather turns truly summery again.

"It's just part of the transition from spring through to the more settled weather of January. So I'd say we've got a few more weeks before it starts to dry out - but hopefully not too much, because then the farmers get upset," Mr Duncan said.