Major cities hit by 25% rise in extremely hot days since 90s

The world's biggest capital cities are now sweltering under 25% more extremely hot days each year than in the 1990s, an analysis has found.

- Damian Carrington

Without urgent action to protect millions from high temperatures, more and more will suffer in the dangerous conditions, analysts said.

From Washington DC and Madrid to Tokyo and Beijing, the analysis shows a marked rise in hot days as the climate crisis intensifies. Overall, the assessment by the International Institute for Environment and Development (IIED), found the number of days above 35C in 43 of the world's most populous capitals rose from an average of 1,062 a year from 1994 to 2003, to 1,335 from 2015 to 2024.

The rise was seen across the world, with the average number of days above 35C doubling in Rome and Beijing, and tripling in Manila. In Madrid, there are now an average of 47 days a year over 35C, compared with 25 before. In London, which has a relatively cool climate, the number of days above 30C doubled.