Archive · 30 Sep 2025
World Cities Experience a Quarter More Extremely Hot Days
Imagine big cities all over the world getting hotter!
Scientists looked at how many days were super hot in many cities, and they found things are getting worse.
The number of very hot days has jumped up quite a bit, especially in the last few years, like 2024.
Some cities, like Delhi, are really feeling the heat, and places with poor housing are struggling the most.
The scientists are worried because cities aren't prepared, especially in poorer areas.
They say cities need to improve buildings and make plans to protect people from the heat.
The study analyzed temperature data from 43 cities.
There has been a 26% increase in very hot days (above 35°C) since 1994.
2024 recorded the highest number of very hot days.
Cities in Europe, like Rome and Madrid, also saw an increase in extremely hot days.
Poor housing and infrastructure in cities make residents vulnerable to high temperatures.
- Who
- Researchers at the International Institute for Environment and Development (IIED)
- What
- Found a significant rise in the number of extremely hot days in major cities worldwide.
- When
- The study analyzed data from 1994 to 2024, with the most recent data points highlighting 2024 as the hottest year.
- Where
- 43 key cities worldwide were analyzed.
- Why
- To assess the impact of rising global temperatures on urban areas and to highlight the vulnerability of residents to heat stress.
- Cities Studied
- 43 key cities, including the 40 most populous capitals
- Timeframe Studied
- 1994-2024
- Increase in Very Hot Days
- 26% increase in days above 35°C
- Highest Year
- 2024 recorded the most very hot days (1,612)
- Cities With Record Hot Days in 2024
- Antananarivo, Cairo, Johannesburg, Kinshasa, Manila, Rome, Tokyo, Washington DC, Yaounde