18/05/2026 – Weather in Cornwall

Cornwall Set for a Soggy Start Before a Sun-Soaked Friday

Brollies out, then sun cream on. The Met Office forecast for the week ahead suggests Cornwall is in for a proper game of weather two halves, with rain and thundery showers giving way to what could be the warmest day of the week by Friday.

A wet Monday across the Duchy

The week has opened on a damp note, with a band of rain breaking up into bright spells and scattered showers across the South West. Forecasters expect those showers to ease a little through the afternoon, but a fresh band of rain is set to push into the far southwest later in the day. Temperatures will struggle, peaking at around 14°C.

Tonight brings late spells of sunshine in the east, but rain will spread across the region overnight, pushed along by blustery winds. The upside is a milder night than Cornwall has seen recently, with lows of 9°C.

Thundery showers possible on Tuesday

Tuesday looks lively. Any lingering rain in the east should clear quickly, leaving a blustery day of sunshine and showers. The Met Office warns those showers could be heavy and possibly thundery before easing later in the day. Temperatures will climb a touch to 17°C.

Warmer weather waiting in the wings

Wednesday will hold on to the unsettled theme with further showers likely, but the picture shifts from Thursday onwards. The Met Office expects conditions to turn drier, brighter and warmer as the week goes on.

Friday is the one to watch. Forecasters describe it as mostly sunny and very warm, although the odd shower could still develop later in the day.