Your weather: Regions to bask in warm temperatures under high pressure system

Warm summer temperatures in the low 20s are expected to blanket much of New Zealand this week.

Aucklanders can expect today to hit a top of 21C as a high pressure system moves over the North Island, bringing largely stable weather conditions.

Hamilton is expecting a high of 23C, while a top of 20C and clear skies are tipped for New Plymouth and 19C for Wellington, where a southerly breeze will develop late.

Showers are expected in Thames and Tauranga before moving south to the East Cape and Gisborne with tops of 20C expected in most regions.

In the South Island clear skies are forecast for Queenstown and Christchurch with highs of 20C and 19C, respectively.

MetService meteorologist Rob Kerr said the story of this week's weather was really about how long the high pressure ridge stayed over the country.

He said it should last over the North Island into next week while also moving over the South Island from tomorrow.

But a change moving northwest could then bring rain to parts of the South Island from Thursday with potentially heavy falls on the West Coast on Friday.

The conditions meant some inland parts of the South Island were more than 10 degrees warmer than normal for this time of the year, according to forecaster WeatherWatch.

Inland cities in the North Island, including Hamilton, Palmerston North and Invercargill were also likely to experience above average temperatures.

However, some coastal fringes won't be as warm because of the cooling effect of sea breezes.

This was likely to be the case in Auckland, Wellington, Tauranga and Napier, where temperatures are "officially" recorded at the airports.

Yet while the days are warmer in inland areas, the nights are often cooler than normal due to the clear skies releasing the heat, Weatherwatch said.

Apart from the chance of showers tomorrow, Auckland and Hamilton residents can expect sunny skies and tops of 22C and 23C for the rest of the week.

Wellington and Tauranga can also expect sunny skies and highs in the 20s into the weekend.

Christchurch can expect warm weather up to 23C along with cloudy skies for the rest of the week.