The heat wave once again disrupts the Intercités Clermont-Ferrand - Paris line. This Thursday, June 18, 2026, the SNCF is cancelling several services to prevent air-conditioning failures on its aging trains. The Puy-de-Dôme (63) has been placed on yellow heat‑wave vigilance by Météo-France, which forecasts peak temperatures around 35 °C this afternoon.
Nothing surprising for regulars on this line, already tested at the start of the week by long delays. When the temperature rises, the venerable Corail trains eventually throw in the towel, and SNCF would rather act in anticipation than leave passengers to stew in the heat.
The problem is essentially technical. While Intercités trains are theoretically air-conditioned, some Corail train sets — with the oldest reaching 50 years — can no longer run once the thermometer climbs above 33 °C, for safety reasons. Beyond that threshold, the risk of a cooling system failure becomes too high.
Practically, the heat can quickly become stifling in a car with no fresh air, forcing inspectors to shuffle passengers to other cars. To limit the damage, SNCF has already barred one out of seven cars from bookings and has painted the roofs white on some trains to reduce the heat inside.
As with every heat wave, it’s the midday services at the peak of the heat that are affected. SNCF is targeting the early-afternoon round trips, the ones most exposed to overheating.
On this line, the trains usually affected are Intercités 5966 (departing Clermont around 10:27) and 5970 (around 13:28), as well as 5959 and 5963 on the Paris-Bercy to Clermont leg in the early afternoon. Before you set off, we advise checking your exact journey on SNCF Connect, as the list can change with temperature developments.
If your ticket is affected, don’t panic. SNCF is offering a full refund or a free exchange, available directly from the app or the SNCF Connect website. You can also opt for another Intercités service that’s still running, keeping in mind that these trains are often near capacity during heat waves.
To track how warnings evolve and adjust your travel, the most reliable source remains Météo-France's forecasts, which update their department-by-department maps.
This summer’s ordeal has sadly become a fixture on the Clermont-Paris line. Commuters are waiting for the arrival of the new Oxygène trains, expected in 2027, hoping the current fleet will hold up until then. In the meantime, it’s wise to plan your trip in advance and keep an eye on the thermometer.
