An enormous high pressure system is perfectly centred across both main islands of NZ but stretches from Fiji to eastern Australia and all the way down to near Antarctica.

WeatherWatch.co.nz says from north to south the high (anticyclone) is around 5000km in distance.

New Zealand is 1600km long from north to south.

This huge high means we'll have a couple of cold nights ahead but warmer than average afternoons for many places inland both today and tomorrow.

Due to the time of year WeatherWatch.co.nz has dubbed this high an "Easter Egg high" because of the shape of the centre directly over NZ.

"The high lingers for Good Friday too - but the rain band that will bring rain to all parts of NZ at some point over the long weekend first arrives in the South West corner of the South Island on Friday PM."