Car color could be raising temperatures in cities, study shows
Dark-colored vehicles may be silently driving up urban temperatures by intensifying the heat radiated into city streets, according to new research from Portugal.
Craig Saueurs reports for Euronews.
In short:
- A study from the University of Lisbon found that black cars parked in summer sun raised surrounding air temperatures by nearly 4°C, while white cars had a far smaller effect.
- Dark-colored paint absorbs up to 95% of sunlight, warming the car’s metal shell, which then radiates heat directly into the air — amplifying the urban heat island effect.
- Repainting dark cars in lighter shades could double the reflectivity of city streets and modestly lower near-surface air temperatures, especially in densely packed, heat-prone urban areas.
Key quote:
“Now picture thousands of cars parked across a city, each one acting like a little heat source or a heat shield. Their color can actually shift how hot the streets feel.”
— Márcia Matias, University of Lisbon researcher
Why this matters:
Cities are getting hotter, and not just because of climate change. Urban infrastructure — from asphalt to glass towers — traps and radiates heat, a phenomenon known as the urban heat island effect. This makes city neighborhoods measurably warmer than nearby rural areas, especially at night when stored heat is slowly released. In Europe, where more than two-thirds of the population lives in cities, these heat spikes are becoming a public health hazard, especially during record-setting heatwaves. Vehicles, especially fleets of dark-colored ones, may be a more important factor in this heat dynamic than previously thought.
Related: Urban heat is making European cities dangerously hotter than surrounding areas
