Muggy air is hanging around - right across the country

MetService is forecasting a scorching end to spring - with temperatures nearing 30 degrees tomorrow.

Metereologist Lewis Ferris says a northwesterly wind's moving up from the south - dragging in heat from the Tasman Sea and warming up eastern parts, in particular.

He says it will also drive up the mercury overnight.

Ferris says people might be kicking off their duvets - with areas like Central Otago and Southland not dropping below 15 degrees.

Ferris says the North Islanders should also expect temperatures in the mid-teens overnight.