Heat stress - Cities and FUAs — Mean population exposure to heat stress by country
This dataset provides an indicator of population exposure to heat stress. Data sources and methodology The indicator uses the Universal Thermal Comfort Index (UTCI). The UTCI enables to assess the impact of atmospheric conditions on the human body by considering air temperature, wind, radiation and humidity. UTCI...
What the numbers show
Heat stress - Cities and FUAs — Mean population exposure to heat stress is currently reported for 2 countries. The highest value is 14.23 Days per year in Luxembourg; the lowest is 0.5239 Days per year in Armenia.
The median across all reporting countries is 7.38 Days per year, and the mean is 7.38 Days per year.
The gap between the highest and lowest reporting country is a factor of about 27.
Over the past decade 1 countries rose and 1 fell. The largest increase was in Luxembourg (up 1.8%), and the largest decrease in Armenia (down 10.4%).
Heat stress - Cities and FUAs — Mean population exposure to heat: full country ranking
| # | Country | Latest | Year | 10-year change | Trend |
|---|---|---|---|---|---|
| 1 | Luxembourg | 14.23 Days per year | 2025 | up 1.8% | volatile |
| 2 | Armenia | 0.5239 Days per year | 2025 | down 10.4% | rising |
Regions and income groups
Aggregates are excluded from the country ranking above so that a region can never outrank a country.
- Sincelejo 365 Days per year
- Barrancabermeja 365 Days per year
- La Dorada 365 Days per year
- Caucasia 365 Days per year
- Sabanalarga 365 Days per year
- El Carmen de Bolívar 365 Days per year
- Sacramento 130.46 Days per year
- Toledo 111.8 Days per year
- Treviso 73.19 Days per year
- Coimbra 63.51 Days per year
- Braga 61.02 Days per year
- Santiago 50.21 Days per year
- Montería 364.87 Days per year
- Porto 33.64 Days per year
- Magangué 364.44 Days per year
- Nantes 25.98 Days per year
- Maicao 363.06 Days per year
- Valparaíso 15.5 Days per year
- Colima 356.81 Days per year
- Lazaro Cardenas 356.44 Days per year
- Acapulco de Juarez 354.1 Days per year
- Arauca 353.51 Days per year
- Tapachula 351.34 Days per year
- Riohacha 350.21 Days per year
- Cayenne 346.99 Days per year
- Iguala de la Independencia 344.47 Days per year
- Culiacan 340.59 Days per year
- Quibdó 339.29 Days per year
- Merida 333.67 Days per year
- Apatzingan 328.83 Days per year
- Aguachica 326.74 Days per year
- Tepic 326.68 Days per year
- Othon P. Blanco 325.84 Days per year
- Apartadó 324.82 Days per year
- Villahermosa 324.82 Days per year
- Ocaña 315.75 Days per year
- Fundación 315.38 Days per year
- Cúcuta 313.68 Days per year
- Buenaventura 313.5 Days per year
- Navojoa 310.71 Days per year
About this data
This dataset provides an indicator of population exposure to heat stress. Data sources and methodology The indicator uses the Universal Thermal Comfort Index (UTCI). The UTCI enables to assess the impact of atmospheric conditions on the human body by considering air temperature, wind, radiation and humidity. UTCI values from 32°C to 38°C are considered as strong heat stress, from 38°C to 46°C as very strong heat stress, and above 46°C as extreme heat stress. Population exposure to heat stress was computed using the hourly thermal comfort indices grids from the Copernicus Climate Data Store (Di Napoli C. et al.). For each 0.25° by 0.25° grid cell, the number of days for which the maximum UTCI value is above each heat stress threshold (32°C, 38°C and 46°C) is computed. FUA and city level indicators correspond to the population-weighted average number of days above each heat stress threshold, obtained by intersecting the computed grid with the Global Human Settlement Population layer (European Commission, GHSL Data Package 2023). These estimates may differ from official subnational climate statistics due to differences in methodological approaches, such as the use of reanalysis based top down modelling versus in situ observations, along with variations in input data sources, spatial resolution, and the models and algorithms used to generate temperature estimates. Defining FUAs and cities The OECD, in cooperation with the EU, has developed a harmonised definition of functional urban areas (FUAs) to capture the economic and functional reach of cities based on daily commuting patterns (OECD, 2012). FUAs consist of: A city – defined by urban centres in the degree of urbanisation, adapted to the closest local administrative units to define a city. A commuting zone – including all local areas where at least 15% of employed residents work in the city. The delineation process includes: Assigning municipalities surrounded by a single FUA to that FUA. Excluding non-contiguous municipalities. The correspondence table between SAUs and FUAs/cities is available in parquet and csv format. The definition identifies 1 272 FUAs and 1 269 cities in all OECD member countries except Costa Rica and three accession countries. Cite this dataset OECD Regions, cities and local areas database (Heat stress - Cities and FUAs), http://oe.cd/geostats Further information OECD Local Data Portal OECD Regions and Cities at a Glance For questions and/or comments, please email CitiesStat@oecd.org