Summer 2026 averaged 16.5°C across the UK, the highest in a series that starts in 1884 and 0.4°C above the record 2025 set. Seven of the ten hottest summers have come since 2000, and the warmth carried on into a joint-fourth-warmest September.
The UK’s mean temperature for June, July and August 2026 was 16.51°C in the Met Office’s HadUK-Grid series, against 16.12°C in 2025.1 The Met Office has called the result provisional and described the old mark as a record “set just last year”.2 It is not a single hot spell. Day and night temperatures are averaged across the whole country and all three months.
The year-to-year line is noisy, but the ten-year average beneath it has moved a long way. It stood at 13.53°C in 1913 and is 15.37°C now. This summer was 1.9°C above the 1991–2020 average and 2.9°C above the 1884–1913 average, both computed by Noodle News from the same series.1
For decades 1976 was the summer every other was measured against. It now ranks seventh.2 Of the ten hottest summers since 1884, only 1976, 1995 and 1933 come from before 2000. The cluster below the top two is very tight: 2018, 2006, 2003, 2022 and 1976 sit within 0.06°C of each other, so their order can shift with small revisions.1
The Met Office’s attribution team estimates that a summer this hot was around 130 times more likely because of human-induced climate change. Without it, such a summer would be rarer than one in 1,000 years; in today’s climate it is roughly a one-in-nine-year event.2 That is a modelled estimate, not a measurement, and it is the Met Office’s figure, not ours.
September 2026 averaged 14.6°C, 1.6°C above its 1991–2020 average and level with 1949 and 2016 as the joint-fourth warmest on record.3 Five of the six warmest Septembers have now come since 2006.1 The warmth was uneven. England was 2.0°C above average and got 65% of its usual rain, while Scotland was 1.0°C above average and got 137% of its usual rain.3
The 2026 figures are provisional and the Met Office revises them as late station data arrives. It already revised the summer’s peak temperature on 17 September.2 A shift of a few hundredths of a degree would not change the summer record, which leads by 0.39°C, but it could reorder the near-ties below it. Station coverage before the mid-20th century was thinner, so the early part of the series carries more uncertainty than the recent part. Two record summers do not tell us whether next summer will be hotter. They show where the distribution now sits.