Hottest Summer on Record for UK (and Hereford)

 The meteorological summer of 2025 (June, July & August) was the hottest on record according to the UK Met Office (based on the average temperature (Figure 1) or average minimum temperature over the three summer months). Herefordshire (circled in Figure 1) was 1.5 ℃ to 2 ℃ warmer than the long-term (1991  - 2020) average.

Figure 1: Average UK Temperature Anomalies for Summer 2025

My weather station data only goes back as far as 2020 so I cannot say whether this summer was the hottest ever in Hereford. However, we can say the summer of 2025 in Hereford was comfortably the hottest summer of the current decade (Figure 2). Compared to the 2020 - 2024 summer mean (17.5 ℃) in Hereford, this summer was 1.5℃ warmer.

Figure 2: Mean Summer Daily Temperatures in Hereford

Whenever we have a hot summer, the media (social & mainstream) always harks back to the legendary summer of 1976. In 1976, we were both in Norwich: Mary was working at the John Innes Institute and I was doing my PhD at the University of East Anglia. It certainly was a hot, dry & sunny summer in 1976 - indeed the hottest on record at that time. However, as Figure 3 demonstrates, it was not as hot as this year's summer based on average daily temperatures. Herefordshire and Norwich/Norfolk are marked on the map in Figure 3 for reference.

Figure 3: Average UK Temperature Anomalies for the Summer 1976

August 2025 recorded a single heatwave in Hereford that lasted eight days (10th - 17th) which took the number of heatwaves this summer up to 5 (Figure 4); the most in a summer season this decade (2020 - 2025).

Figure 4: Number of Summer (JJA) Heatwaves (2020 - 2025)

If we just look at the number of hot days (i.e. >26 ℃), then 2020 was the record breaker with 2022 & 2025 equal in second place (Figure 5). It is possible that 2025 could still overtake 2020 & 2022 if we have a spell of warm weather in the second half of September or October.

Figure 5: Number of Hot Days (>26 ℃)

In summary, in Hereford we have just experienced a very hot summer that included 5 heatwaves. We really need to pull our socks up if we are to avoid some very unpleasant summers in the near future.