Spring equinox is UK's warmest day of year so far

Temperatures have climbed above 21C in parts of England meaning Thursday is the UK's warmest day of the year so far.

According to the Met Office, Northolt in London and Chertsey in Surrey reached 21.3C (70.3F), exceeding the previous high of 19.7C (67.5F) set earlier in March.

Wales has also had its highest temperature of 2025 so far with 20.4C (68.7F) recorded at Gogerddan in Ceredigion - provisionally Wales' warmest spring equinox on record.

The equinox marks the first day of astronomical spring - although weather forecasters tend to refer to meteorological spring which began on 1 March.

Moderate UV levels and high or very high concentrations of tree pollen are also forecast across many parts of the UK.

Temperatures fell to -7.9C (17.8F) in Braemar on Wednesday night and it was a widely frosty start on Thursday across Scotland and northern England.

But under sunny skies temperatures climbed rapidly through the morning, exceeding 21C (70F) in some places during the afternoon.

In fact they got very close to those seen on the warmest spring equinox on record. Cambridge Botanic Garden had a high of 21.5C (70.7F) on 20 March 1972.

England and Wales have had the lion's share of the warmth with Northern Ireland and Scotland remaining a little cooler - although some spots exceeded 16C (61F), well above the seasonal norm.

During this brief spell of warm weather temperatures are roughly 4-7°C (7.2-12.6°F) above the March average.

However, this isn't uncommon for the time of year.

March is a transition season - from winter to spring - during which we often see big temperature swings depending on the direction of the wind.

Although not unusual, this type of warmer spell in spring is made more likely due to climate change.

Scientists from Climate Central, external suggest this week's temperatures have been made at least one-to-three times more likely by climate change across a lot of the UK, and for some regions at least four-to-five times more likely.

The highest-ever March temperature of 25.6C (78.1F) was recorded at Mepal, Cambridgeshire, in 1968.

While Thursday is the peak of the warmth across the UK as a whole, Friday is actually expected to be the warmest day of the week in Scotland with temperatures forecast to rise to 17C (63F).

However cloud and rain will start to arrive in the south and west of England, Wales and Northern Ireland.

The weekend looks generally cooler and more unsettled although temperatures in many areas will remain a little above the seasonal average.

You can keep an eye on your local weather prospects on the BBC Weather app, and check the longer-range forecast in our latest monthly outlook.