18/03/2026 – Weather in Cornwall

Sunshine and 18°C Today: But Frost Could Hit Tonight

Residents across the South West can expect plenty of sunshine over the coming days, with warm afternoons but colder nights as the week progresses.

According to the latest forecast covering Wednesday 18th March to Sunday 22nd March, conditions are set to remain mostly dry with long spells of sunshine.

Sunny and Warm Today

Any mist and fog patches early this morning are expected to clear, leaving a dry and sunny day across the region.

Light winds combined with the sunshine will make it feel warm during the afternoon, with maximum temperatures reaching around 18°C.

Clear Skies but Frost Possible Tonight

Clear skies and light winds are expected overnight, creating conditions where patchy mist and fog may develop during the early hours.

Temperatures are forecast to drop sharply, with a minimum of around 0°C, bringing the possibility of frost in some areas.

Fine Weather Continues Thursday

Thursday 19th March will begin with a chilly start. Once any early mist or fog clears, the day is expected to be dry with warm spells of sunshine and light winds.

Temperatures are expected to reach around 16°C during the afternoon.

Outlook for the Weekend

Looking ahead to Friday through to Sunday, the dry weather is set to continue with sunny spells across the South West.

It will feel a little cooler overall, particularly overnight where clear skies could again lead to chilly conditions.

Light winds are expected to continue through the period.