Spring equinox is provisionally UKs warmest day of year so far

Temperatures have climbed above 20C in parts of England meaning Thursday is - provisionally - the UKs warmest day of the year so far.

According to the Met Office, Northolt in London reached 20.6C (69.1F) by lunchtime, exceeding 2025s previous high of 19.7C (67.5F) set earlier in March.

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

The sun is definitely getting stronger during March as UV levels have risen to moderate.

High or very high levels 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 during the morning, hitting 20C by lunchtime.

More warmth across the UK on Thursday before a dip in temperatures on Friday

Afternoon highs are forecast to reach 12-16C (54-61F) across Scotland and Northern Ireland, with 15-21C (59-70F) expected in England and Wales.

It is not impossible that temperatures could exceed those seen on the warmest spring equinox on record. Temperatures on 20 March 1972 reached 21.5C (70.7F) at Cambridge Botanic Garden.

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

However, this isnt 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 weeks 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.

The dry and warm spell will give way to cooler and more unsettled weather

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.