France braces for an exceptionally early second heatwave before summer begins

France is heading into an exceptionally early second heatwave of the year, with Météo-France warning that the main spike in heat is expected from June 17 to June 21, before summer officially begins.

The national forecaster has already placed 52 departments under yellow heatwave alert. Officials say some areas could be upgraded to orange alert as the forecast becomes clearer, although it is still too early to know whether any department will need the highest red alert.

Forecast highs are expected to range from about 34C to 38C across much of mainland France, with hotspots potentially reaching 40C. The Paris region, the center-east, Rhône-Alpes and parts of southern France are among the areas expected to face the most intense conditions.

Why meteorologists say it is unusual

Météo-France climatologist Matthieu Sorel said the episode would be one of the earliest heatwaves recorded in France. The timing is notable because the heat arrives in mid-June, after another unusually early hot spell in late May and before the official start of summer.

Le Monde reported on June 13 that France was already building toward another very intense and widespread heat event, with forecasters warning at the time that temperatures could climb above 40C in some places. The latest alert on June 16 marks the point at which the threat has become immediate enough for widespread warning levels.

The expected peak around Sunday, June 21, the summer solstice, also adds to the sense of an extended and unusually timed heat episode.

Areas and impacts

The forecast points to a broad national heat event rather than a narrow regional spike. Le Monde said an orange alert could be issued from midday Thursday in the center-east, north of Rhône-Alpes and the Paris region if conditions intensify as expected.

The weather service is also warning about tropical nights, when temperatures stay high overnight and the body gets less chance to recover. That can make heat more dangerous, especially for older people, people with chronic illness and anyone exposed to heat for long periods.

Authorities are urging people to stay cool, drink water and limit strenuous activity during the hottest hours.

Public-health and disruption risks

The stakes go beyond discomfort. Prolonged heat increases the risk of heat-related illness, especially when hot days are paired with warm nights. It also raises drought stress and wildfire risk, particularly in southern France where dry conditions can deteriorate quickly during hot weather.

The timing is also sensitive for schools and public life. The episode arrives during the baccalaureate exam period, and it could affect students, exam halls and families moving across the country. The forecast also comes ahead of the Fete de la Musique and other summer events that may face crowd-safety and heat-management pressure.

France has already experienced an unusually early pattern of heat in 2026. A late-May heatwave brought record temperatures in parts of the country, and that was followed by another hot spell in early to mid-June before this latest escalation.

What to watch next

The immediate question is whether Météo-France upgrades any departments from yellow to orange, or eventually red, as the hotter air mass settles in.

Forecasters will also be watching whether temperatures actually reach 40C in the warmest areas and how long the hottest conditions last around the solstice.

The French government was due to announce adaptation measures on Wednesday, and more public-health guidance could follow if the heat intensifies further.

For now, the confirmed development is clear: France is facing a nationwide heat warning unusually early in the season, with the risk of a more severe escalation still open.