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

Temperatures in parts of England have climbed to over 21 degrees Celsius, making this past Thursday the warmest day of the year so far in the UK. The UK Met Office reported that temperatures reached 21.3 degrees Celsius (70.3 Fahrenheit) in Northolt, London, and Chertsey, Surrey, surpassing the previous high of 19.7 degrees Celsius (67.5 Fahrenheit) set in early March. This unseasonably warm weather has been welcomed by many after a long winter.

Wales also experienced its highest temperature of 2025 so far, with 20.4 degrees Celsius (68.7 Fahrenheit) recorded in Gogerddan, Ceredigion, which temporarily became Wales' warmest equinox day on record. The equinox marks the first day of astronomical spring, although weather forecasters tend to refer to the meteorological spring, which starts on March 1st. This difference in definition can sometimes lead to confusion about the start of the season.

Much of the UK was expected to experience moderate UV levels and high or very high tree pollen counts. However, on Wednesday night, temperatures in Braemar fell to minus 7.9 degrees Celsius (17.8 Fahrenheit), and frost was widespread across Scotland and northern England on Thursday. But under sunny skies, temperatures rapidly climbed during the morning, exceeding 21 degrees Celsius (70 Fahrenheit) in some areas by the afternoon. This contrast highlights the variability of spring weather.

In fact, the temperatures were very close to the warmest equinox day on record. On March 20, 1972, the Cambridge Botanic Garden recorded a maximum temperature of 21.5 degrees Celsius (70.7 Fahrenheit). England and Wales enjoyed most of the warmth, while Northern Ireland and Scotland were relatively cooler, although temperatures in some areas exceeded 16 degrees Celsius (61 Fahrenheit), well above seasonal norms. This brief spell of warmth saw temperatures around 4-7 degrees Celsius (7.2-12.6 Fahrenheit) higher than the average for March.

However, this is not uncommon for this time of year. March is a transitional season from winter to spring, during which we often see large fluctuations in temperature due to varying wind directions. While not uncommon, climate change is making the occurrence of such warmer spells in spring more likely. Scientists at Climate Central stated that climate change has made the temperatures this week at least one to three times more likely across most of the UK, and even four to five times more likely in some areas.

The highest March temperature on record is 25.6 degrees Celsius (78.1 Fahrenheit), recorded in Mepal, Cambridgeshire, in 1968. While Thursday was the warmest day overall for the UK, Friday was actually forecast to be the warmest day of the week for Scotland, with temperatures expected to rise to 17 degrees Celsius (63 Fahrenheit). However, cloud and rain will begin to arrive in southern and western England, Wales, and Northern Ireland. The weekend looks generally cooler and unsettled, although temperatures will still be slightly above seasonal averages in many areas.