Summer heat will remain across large parts of France on Sunday, except for some local cool spots. Forecasters expect the polar jet stream to undulate overhead. Once that happens, temperatures could become noticeably cooler, with the arrival time for cooler air varying by location.

Regional forecasts keep pointing to a warm pattern in parts of the south. Some areas will hold on to the warmth, while others may see the cooler air arrive sooner. Exactly when it arrives varies by place.