23/06/2026 – Weather in Cornwall

Cornwall faces 38°C as a hot, humid spell builds this week

Cornwall is about to get a proper taste of summer, and the muggy nights might be harder going than the bright days.

The latest forecast for the South West points to extremely hot and humid conditions building across the region this week, with the mercury set to climb toward 38°C by Wednesday. Light winds mean little relief from the heat, though the coast should stay a touch fresher than inland.

Today and tonight

Any patchy cloud first thing is expected to break and clear, leaving plenty of strong sunshine. It will feel very hot and humid through the afternoon with light winds, and a maximum of around 35°C. The coast holds onto a slightly fresher feel.

The warmth carries into the evening with some late sunshine. Then comes a very warm and muggy night, possibly with a few mist and fog patches forming. The temperature is not expected to drop below about 20°C.

Wednesday is the peak

Wednesday looks like the hottest day of the run. Very hot and humid again, with strong sunshine through the day and light winds. It stays very warm into the evening. The maximum could reach 38°C.

Thursday to Saturday

Thursday turns extremely hot and humid, particularly across the south. There will be strong sunshine at times, but the cloud builds through the day and showers are possible. From Friday it starts to feel slightly cooler.