High pressure south of Australia is the main driver of our weather this week but a sub-tropical low and a couple of cold fronts are in the mix.

Colder air spreads up NZ on Monday and then again on Wednesday – neither are majorly aggressive but the further south you are the more noticeable it is.

At the same time a low is forming north of New Zealand. This encourages a south-east flow over the North Island bringing some showers/small area of rain to the top of the island in particular, coming in from the east to south east. Western areas look driest.

Frosts are expected through the South Island’s interior on Tuesday morning. See frost forecasts in the our new app.

The subtropical low is expected to deepen east of NZ and, for the most part, remain offshore.

• WeatherWatch.co.nz