Heat stress - Cities and FUAs — Mean population exposure to heat in Boulder
Boulder: Heat stress - Cities and FUAs — Mean population exposure to heat was 58.37 Days per year in 2025. ▲ Rising
Heat stress - Cities and FUAs — Mean population exposure to heat in Boulder, 1981–2025
Source: Organisation for Economic Co-operation and Development. Measured in Days per year.
Analysis
Boulder recorded 58.37 Days per year for heat stress - cities and fuas — mean population exposure to heat in 2025.
The figure is down 22.2% on the previous year and up 18.2% over ten years.
Over the whole period, heat stress - cities and fuas — mean population exposure to heat in Boulder peaked at 77.27 Days per year in 2012 and was at its lowest, 21.9 Days per year, in 1992.
That places Boulder 497th out of 1315 regions with data for 2025, putting it in the middle of the range.
The long-run direction has been consistently rising across the 45 years of available data.
Heat stress - Cities and FUAs — Mean population exposure to heat in Boulder, year by year
| Year | Days per year | Change |
|---|---|---|
| 1981 | 43.95 Days per year | — |
| 1982 | 33.58 Days per year | -23.6% |
| 1983 | 32.78 Days per year | -2.4% |
| 1984 | 23.23 Days per year | -29.1% |
| 1985 | 35.3 Days per year | +52.0% |
| 1986 | 30.26 Days per year | -14.3% |
| 1987 | 33.9 Days per year | +12.0% |
| 1988 | 53.97 Days per year | +59.2% |
| 1989 | 29.78 Days per year | -44.8% |
| 1990 | 36.57 Days per year | +22.8% |
| 1991 | 26.02 Days per year | -28.8% |
| 1992 | 21.9 Days per year | -15.8% |
| 1993 | 29.82 Days per year | +36.2% |
| 1994 | 61.36 Days per year | +105.7% |
| 1995 | 43.39 Days per year | -29.3% |
| 1996 | 36.02 Days per year | -17.0% |
| 1997 | 25.17 Days per year | -30.1% |
| 1998 | 36.46 Days per year | +44.9% |
| 1999 | 32.18 Days per year | -11.7% |
| 2000 | 61.25 Days per year | +90.4% |
| 2001 | 47.78 Days per year | -22.0% |
| 2002 | 63.52 Days per year | +33.0% |
| 2003 | 49.37 Days per year | -22.3% |
| 2004 | 23.81 Days per year | -51.8% |
| 2005 | 49.94 Days per year | +109.7% |
| 2006 | 61.3 Days per year | +22.8% |
| 2007 | 64.68 Days per year | +5.5% |
| 2008 | 44.05 Days per year | -31.9% |
| 2009 | 29.87 Days per year | -32.2% |
| 2010 | 47.91 Days per year | +60.4% |
| 2011 | 53.15 Days per year | +10.9% |
| 2012 | 77.27 Days per year | +45.4% |
| 2013 | 65.06 Days per year | -15.8% |
| 2014 | 41.34 Days per year | -36.5% |
| 2015 | 49.4 Days per year | +19.5% |
| 2016 | 52.53 Days per year | +6.3% |
| 2017 | 53.44 Days per year | +1.7% |
| 2018 | 59.84 Days per year | +12.0% |
| 2019 | 57.85 Days per year | -3.3% |
| 2020 | 70.62 Days per year | +22.1% |
| 2021 | 69.66 Days per year | -1.4% |
| 2022 | 75.59 Days per year | +8.5% |
| 2023 | 42.78 Days per year | -43.4% |
| 2024 | 75.05 Days per year | +75.4% |
| 2025 | 58.37 Days per year | -22.2% |
Averages by decade
| Decade | Average | Lowest | Highest | Years |
|---|---|---|---|---|
| 1980s | 35.19 Days per year | 23.23 Days per year | 53.97 Days per year | 9 |
| 1990s | 34.89 Days per year | 21.9 Days per year | 61.36 Days per year | 10 |
| 2000s | 49.56 Days per year | 23.81 Days per year | 64.68 Days per year | 10 |
| 2010s | 55.78 Days per year | 41.34 Days per year | 77.27 Days per year | 10 |
| 2020s | 65.35 Days per year | 42.78 Days per year | 75.59 Days per year | 6 |
More population data for Boulder
- Population by age and sex - Cities and FUAs 330,262 Persons (2024)
- Foreign-born population - Cities and FUAs 10 Percentage of population (2023)
- Population and built-up density - Cities and FUAs — Urbanised area 54 Square kilometres (2030)
Frequently asked questions
- What is heat stress - cities and fuas — mean population exposure to heat in Boulder?
- Heat stress - cities and fuas — mean population exposure to heat in Boulder was 58.37 Days per year in 2025, according to Organisation for Economic Co-operation and Development.
- What is the highest heat stress - cities and fuas — mean population exposure to heat recorded in Boulder?
- The highest recorded value was 77.27 Days per year in 2012.
- What is the lowest heat stress - cities and fuas — mean population exposure to heat recorded in Boulder?
- The lowest recorded value was 21.9 Days per year in 1992.
- How does Boulder rank for heat stress - cities and fuas — mean population exposure to heat?
- Boulder ranks 497th out of 1315 regions with data for 2025.
- Is heat stress - cities and fuas — mean population exposure to heat rising or falling in Boulder?
- Over the last ten years it is up 18.2%. The long-run trend across the full record is rising.
- Where does this Boulder data come from?
- The figures come from Organisation for Economic Co-operation and Development, published as part of Heat stress - Cities and FUAs — Mean population exposure to heat stress. Statizoid updates them automatically from the source API.
Download this data
CSV · JSON — 45 observations, free to reuse under OECD Terms and Conditions (attribution required).
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