Beyond the Thermometer: 5 Heat Metrics That Drive Better Decision-Making

This briefingS briefing from the World Resources Institute explains five different heat metrics—land surface temperature, air temperature, heat index, wet bulb globe temperature, and thermal comfort indices—and how they serve different purposes for urban planning and public health. It argues that while traditional metrics provide regional or surface-level data, thermal comfort indices are necessary forSSS to understand the local, human-scale experience of heat and to design effective interventions like shade and green space.

• Different heat metrics serve distinct purposes in urban heat analysis: land surface temperature (LST) is used for scientific heat mapping and comparing city surfaces, while air temperature is ideal for analyzing ambient weather conditions and comparing temperatures over time.
• Heat index and wet bulb globe temperature (WBGT) are used to predict how the human body reacts to weather. The heat index adjusts air temperature based on humidity, while WBGT adds direct sunlight and wind speed to the calculation to determine heat load.
• Thermal comfort indices provide the most detailed assessment of human heat exposure by calculating the cumulative effects of radiation, air temperature, wind, and humidity at a very local scale (one to five meters). These metrics are often calculated using three-dimensional models that account for buildings, tree canopy, and land use.
• The choice of metric should align with the specific urban goal: air temperature is best for lowering citywide temperatures or reducing ground-level ozone, while thermal comfort indices are necessary for protecting pedestrians and keeping people cool in transit or public spots.
• Climate projections suggest a nearly 3 degree C (5.4 degree F) rise in temperature by 2100 if greenhouse gas emissions are not significantly reduced, which will disproportionately affect the more than 4 billion people living in cities due to urban characteristics like pavement and lack of green space.

APA

World Resources Institute (2025). Beyond the Thermometer: 5 Heat Metrics That Drive Better Decision-Making. https://www.wri.org/insights/beyond-thermometer-measuring-heat

Chicago

World Resources Institute. Beyond the Thermometer: 5 Heat Metrics That Drive Better Decision-Making. 2025. https://www.wri.org/insights/beyond-thermometer-measuring-heat.

Wikipedia

{{cite report |author=World Resources Institute |title=Beyond the Thermometer: 5 Heat Metrics That Drive Better Decision-Making |date=17 March 2025 |url=https://www.wri.org/insights/beyond-thermometer-measuring-heat |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{worldresourcesinstitute2025beyond, author = {{World Resources Institute}}, title = {{Beyond the Thermometer: 5 Heat Metrics That Drive Better Decision-Making}}, institution = {World Resources Institute}, year = {2025}, month = mar, url = {https://www.wri.org/insights/beyond-thermometer-measuring-heat}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }