A front is moving northwards over the country today with northerly quarter winds strengthening ahead of it, says WeatherWatch.

"Then changing to westerly in behind. Mostly this affects the South Island today with heavy rain in the west and strong winds out east then the lower North Island sees rain overnight," says a WeatherWatch spokesperson.

"Later on or overnight a trough moves into the far south bringing heavy rain and a southerly wind change, this becomes strong with gales likely to develop about coastal parts."

There are heavy rain and wind watches / warnings out regarding today's activity, some of these carry over into Tuesday.

North Island

In the North Island there is a mix of sun and cloud with areas of cloud thicker this morning for some. There may be a few light showers for eastern Bay Of Plenty and Taranaki down through to Kapiti in the west but thinning out this afternoon.

The east coast has a mainly sunny day, with some high cloud later. Winds will be mostly north to northwest but tending west to southwest for Auckland up through to western Northland this afternoon. Rain moves in overnight for Taranaki through to Wellington.

South Island

The South Island will be cloudy along the West Coast with showers today. Rain moves into South Westland this morning becoming heavy with a chance of thunderstorms, and heavy rain should be reaching Buller this evening, with northerlies changing to westerly later.

Nelson and Marlborough are dry for much of today with sun and developing high cloud. Rain moves in later this evening then clears towards dawn on Tuesday.

Canterbury is mainly dry with increasing high cloud, northerly winds will strengthen especially through North Canterbury with gales there later today. Later this afternoon or evening rain starts to spread from the west as a front moves over - with heavy rain in the high country around the same time.

Overnight winds will be becoming strong from the northwest for all with gales possible after the rain clears.

There are a few spits or showers for Southland this morning, rain for all this afternoon, and rain this evening or overnight becoming heavy as southerly winds strengthen with coastal gales likely.