What is causing the UK's unexpected warm weather?

The warm weather is being caused by east to south-easterly winds passing over higher ground, a phenomenon known as the Foehn effect, which boosts temperatures.

When will the UK experience the hottest day of 2026?

Wednesday is predicted to be the warmest day of the week, with temperatures possibly reaching 20C in parts of west Wales and western England.

Will the UK be warmer than other European capitals this week?

Yes, the UK is forecast to be several degrees warmer than Athens throughout the week.

Home / Weather / UK Heatwave: 20C Warmth Expected This Week

UK Heatwave: 20C Warmth Expected This Week

17 Mar

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Summary

Temperatures could reach 20C in Wales and western England.
The Foehn effect is causing the unexpected temperature boost.
UK temperatures will be warmer than Athens this week.

UK Heatwave: 20C Warmth Expected This Week

Warm weather is forecast for the UK this week, with temperatures expected to peak around 20C in Wales and western England on Wednesday. This anticipated high surpasses the current 2026 record of 18.7C.

The unexpected warmth is driven by east to south-easterly winds interacting with high pressure, a phenomenon known as the Foehn effect. Forecasters predict temperatures in the south and west could reach 18C to 19C, with a possibility of 20C.

While England anticipates sunny afternoons after cloudy starts, Scotland and Northern Ireland are expected to endure overcast conditions with rain. The warmer weather is set to continue into Thursday before cooling towards the seasonal average of 14C by Friday.

Despite the daytime warmth, forecasters warn of chilly nights due to a large diurnal temperature range, with some areas experiencing air frost. The UK is expected to remain several degrees warmer than Athens throughout the week.

Disclaimer: This story has been auto-aggregated and auto-summarised by a computer program. This story has not been edited or created by the Feedzop team.