Heatwaves in Île-de-France affect public transport usage, study finds

Saturday 13 June 2026 - 15:27

A recent study has shown that heatwaves significantly influence public transport usage in the Île-de-France region, with rising temperatures leading to measurable changes in commuter behavior across buses, trains, and regional rail services.

Conducted with the participation of the Institut Paris Région and Transilien SNCF Voyageurs, the research analyzed mobility data collected between 2023 and 2025. It found that public transport usage remains relatively stable between 0°C and 25°C, but begins to decline as temperatures rise beyond that threshold.

During hot weather conditions, bus usage appears to be the most affected mode of transport, dropping by up to 11% when temperatures reach around 30°C compared to milder conditions. Tram services experience a smaller decline, while RER and regional train usage decreases by approximately 4% under similar conditions.

The study also highlights that extreme heat episodes can have a stronger impact. During two recent heatwaves, one in September 2023 and another between late June and early July 2025, bus usage fell between 8% and 20%, while RER and train travel dropped by around 12%.

Interestingly, the metro system is less affected by high temperatures, with a maximum decline of around 8%, likely due to its underground infrastructure offering cooler conditions compared to surface transport.

Researchers also observed that on extremely hot weekdays, reduced rail usage can represent nearly 150,000 fewer trips, a figure comparable to the total daily traffic of some suburban rail lines.

Beyond heatwaves, the study also confirms that other weather conditions such as rain, snow, and ice have an even greater impact on public transport usage, often causing more significant disruptions than high temperatures.

Overall, the findings underline the growing “weather sensitivity” of urban mobility patterns, highlighting how climate conditions increasingly shape daily transportation choices in major metropolitan areas like Paris.