Pairing satellite data with geolocated posts, researchers find heat becomes a public concern above 25°C and weighs heaviest in dense, hot neighborhoods.
A heat map can tell a city where it is hottest. It cannot tell officials who is lying awake at 3 a.m., who is forced to wear long trousers in a sweltering workplace, or who is choosing between an open window and a lungful of smog. A team of European researchers has tried to fill that gap by listening to what people say about heat online.
Writing in the IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, researchers from the University of Würzburg, the German Aerospace Center (DLR) and Mendel University in Brno combined satellite observations, weather-station measurements, data on urban form, census information and geolocated social media posts to study Mexico City in 2022.
“Satellites and weather stations can tell us where it is hot and how hot it is,” said Professor Hannes Taubenböck. “But they cannot reveal whether people cannot sleep, struggle to work, feel unsafe, or suffer during their daily commute. This is the central idea behind the study: moving from measured to experienced heat.”
A tipping point at 25 degrees
The posts revealed a clear threshold. “Once air temperatures exceeded 25°C, heat-related social media posts from Mexico City increased exponentially,” said lead author Richard Lemoine-Rodríguez, “showing that heat becomes a public concern above this threshold.”
Geography mattered too. “Additionally, we found that more heat-related posts were shared from hotter and more densely built parts of Mexico City,” he said.
What people talked about
“What people discussed online showed that heat affects many dimensions of everyday life,” Lemoine-Rodríguez said. “The most common issue was health problems and heat stress, with users describing fatigue, insomnia, physical discomfort, and emotional distress.”
Work was another flashpoint. People described workplaces without adequate cooling and dress codes that barred shorts despite extreme heat, and some argued that work should stop altogether under such conditions. Women reported unwanted attention and harassment when they wore lighter clothing to cope with high temperatures, a burden that rarely shows up in climate adaptation planning.
Getting around the city was its own ordeal. “Other posts focused on public transport and infrastructure; including delays, uncomfortable journeys, and insufficient ventilation or air conditioning,” said Professor Carolin Biewer.
Some residents faced an unpleasant trade-off. “Users also described the situation of having to decide which was the lesser of two evils: exposure to heat or air pollution,” Biewer said. “If they were to open a window to cool down, they would at the same time be forced to inhale polluted air.”
Posts also touched on cooling spaces and air conditioning, concern for animals needing water, social inequality and climate change.
Adapting to the heat people feel
Social media is an imperfect window. Not everyone posts, and those who do are not a random sample of a city’s population. The researchers do not claim the posts replace measurement; rather, they argue that the two together give a fuller picture.
“To adapt cities to increasing heat, it is not enough to know how hot they are,” Taubenböck said. “We also need to understand what that heat means for people.”
Notes
- Lemoine-Rodríguez, R., et al. “From Measured to Experienced Heat: A Multimodal Analysis of Temperature, Urban Form, and Social Media in Mexico City.” IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 27 August 2026. DOI: 10.1109/JSTARS.2026.3728299.
- University of Würzburg. “Beyond temperature: How people experience urban heat.” EurekAlert!, 29 September 2026. https://www.eurekalert.org/news-releases/1145932.
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