official data (Copernicus C3S / ERA5)
August 2026 ties the hottest month ever recorded — oceans hit a new August high
Copernicus’s official August bulletin says the planet just posted the warmest August in the ERA5 record and tied July 2023 as the warmest month of any kind — while extra-polar sea-surface temperatures set an August record and matched the all-month joint high.
Key facts
- Global air (ERA5)
- August 2026 average 16.96°C · +0.85°C vs 1991–2020 — warmest August on record (prior joint August 2023/2024: 16.82°C / +0.71°C)
- All-calendar-months
- August 2026 joint-warmest month ever with July 2023 (16.95°C); difference <0.01°C
- Pre-industrial
- +1.65°C vs estimated 1850–1900 — first month above 1.5°C since November 2025
- Odd calendar
- August 2026 was 0.06°C warmer than July 2026 — rare (ERA5 back to 1940: only 1945, 1951, 1955, 1985 also August > July same year)
- Boreal summer JJA 2026
- Joint-warmest globally with 2024 (+0.69°C vs 1991–2020)
- Extra-polar SST (60°S–60°N)
- August mean 21.07°C — highest August on record (prior 20.98°C in 2023); joint-highest any month with March 2024; daily peak 21.11°C on 24–25 August 2026
- Europe
- Western Europe summer average 21.69°C (+2.54°C vs 1991–2020) — warmest western-Europe summer in ERA5; continent-wide summer third-warmest
- Live
- Later months → live HUD / next C3S bulletin — Desk does not invent a September meter
When the official European climate service stamps +1.65°C vs pre-industrial for a single month and says the seas outside the poles matched their hottest month ever, the instrument panel is not whispering.
Desk reading of C3S Climate Bulletin for August 2026
Note
August did not cool the story. Copernicus says the global average hit 16.96°C — the warmest August in ERA5 and, within a hundredth of a degree, tied with July 2023 as the warmest month of any kind. Against the pre-industrial baseline the month sat 1.65°C hot, the first breach of 1.5°C since late 2025. Outside the polar caps, the ocean surface averaged 21.07°C for August, a monthly record for the date and joint-highest for any month, with a daily peak of 21.11°C late in the month. Western Europe’s summer was the hottest in the same dataset. The bulletin’s own framing ties the air record to record seas and a strengthening equatorial Pacific El Niño — the same ocean that NOAA’s ENSO desk is now calling historic-strength odds.
Attribution: Copernicus Climate Change Service (C3S), implemented by ECMWF — “Surface air temperature for August 2026” Climate Bulletin (ERA5). Press framing twin: C3S release noting joint-hottest month and return above 1.5°C. The Watchers 10 Sep piece = intake pointer only; numbers taken from C3S.
Why it matters
This is the thermostat card for the board: not a local heat wave, the whole-month global average tying the hottest month humans have measured in ERA5, with the ocean panel locked at a record August / joint all-time monthly SST.
Sources
Official data. Live values go to the HUD / source product.