Summer 2026 was 1.20°C warmer than 2022, the second warmest summer in the series, and 2.79°C above the relatively cool summer of 2024. The difference is large enough even within a record containing only five complete summers.
Perhaps a better chart to illustrate how unusual summer 2026 was is the frequency of hot summer days chart, which demonstrates forty-three days above 25°C and fourteen above 30°C. In practical terms, 2026 had enough days to lift the seasonal average, whilst there were frequent episodes of unusually hot weather.
The daily maximum and minimum chart shows the development of the season in even more detail, with the most intense heat arriving in late June, culminating at 35.7°C on the 25th June. July then maintained a high thermal baseline, and August remained warm but was less exceptional.
In a Welsh and UK context, these anomaly maps reinforce the pattern, with positive anomalies covering the entire country, but South Wales lies within the zone that was particularly pronounced. Of course, the data from St Nicholas will not have been replicated exactly across this region – there will have been significant variation.
