MetService says thunderstorms are possible in the lower North Island on Monday.
A rain band that brought gales and downpours on Sunday has now moved away, but warm humid air is inbound from the Tasman sea.
Forecaster Andy Downs says showers are possible in Northland and that more unsettled weather is likely.
He says warm humid air and onshore breezes, paticularly in the west coast of the North Island, could trigger more showers.
Mr Downs also says there is a possibility of isolated thunderstorms from southern Taranaki down to Horowhenua and Kapiiti Coast.