Series · Climate & Perils
Heatwaves
The silent disaster, measured. Two and a half centuries of daily temperature for the places people live, every heat spell detected against its local climate, and the deadliest weather peril told country by country, from the data up.
3 episodes
- Source
- ERA5 / Open-Meteo · HadCET (Met Office)
- Coverage
- Cities 1940 to 2026 · UK 1772 to 2026
- Catalogue
- 22,444 heat spells
- Peril type
- Climatological (temperature)
- Updated
- Jul 2026
Last 12 months & record context · experienced risk
New episode: The World's Thermometer
5 Jul 2026
Episodes
Every tracked city coloured by how far above its own normal it runs, across 85 years of daily heat. Thresholds, anomalies, and why 35 degrees means different things in London and Delhi.
Every detected heat spell in the record, most intense first: where, when, how hot, how far above normal, and how long it held.
The world's longest thermometer record, and the country that hit 40 degrees without air conditioning. From the 1976 siege to the 2022 spike, with the whiplash to minus nine in between.