UK Records Hottest Day of 2025 at 21.3°C on Spring Equinox

The unseasonably warm weather, driven by a 'Spanish plume,' brought high air pollution alerts and allergy warnings, with cooler, unsettled weather expected by the weekend.

The UK experienced its warmest day of the year on March 20, 2025, with temperatures reaching 21.3°C in Northolt, west London, and Chertsey, Surrey.
The warm spell coincided with the spring equinox, marking the start of astronomical spring, though it fell short of the 21.5°C record set in 1972.
The 'Spanish plume,' a meteorological phenomenon bringing warm air from Spain, was identified as the primary driver of the high temperatures.
London issued its first high air pollution alert of the year due to particulate matter from mainland Europe, prompting health warnings for individuals with respiratory conditions.
The warm weather is expected to be brief, with rain and cooler temperatures forecast to return over the weekend, bringing more unsettled conditions.