Intense heatwave warnings spread across France for Sunday and Monday

France is entering the peak of a “historic” early-summer heatwave, with state forecaster Météo-France raising high (orange) alerts for excessive heat in 73 departments on Sunday, June 29, and Monday, June 30. 

The 73 departments affected by the intense heat stretch from Pyrénées-Orientales to Paris and from the Atlantic coast to the Alps. 

The heatwave is forecast to last until at least midweek, with the highest temperatures expected on Tuesday or Wednesday, depending on the region.

Maximum temperatures nearing 40C

On Sunday, temperatures are forecast to reach 35C to 38C across much of the south. 

In the Mediterranean basin, they may locally climb to 39C or even 40C, especially in inland areas. The Paris region will also see sharp increases, with highs of around 32C. 

Only the northern Channel coast is expected to remain below 30C.

Night-time temperatures are also remaining high with 22C to 25C reported overnight Saturday to Sunday in the south-east and up to 26C in some coastal zones. 

This lack of overnight cooling poses additional risks to vulnerable populations.

Heatwave health advice

The Health Ministry advises staying hydrated, avoiding physical exertion during the hottest part of the day, seeking cool or air-conditioned spaces, and checking in on isolated or vulnerable people.

Health professionals are reminding the public that certain medications can make people more susceptible to heat-related illness. 

Drugs such as antidepressants, antihistamines, anti-hypertensives and antipsychotics can interfere with the body’s ability to cool itself or sense heat stress.

Some can also increase the risk of dehydration, heat stroke or sunburn. People taking these medications regularly are advised to consult their doctor or pharmacist if they experience unusual reactions in the heat.

The Health Ministry has reactivated its heatwave advice line, available from 09:00 to 19:00 each day at 0800 06 66 66. 

Fire risk in multiple departments

The intense heat has put more areas at risk of wildfires.

On Saturday, six departments were already on orange alert for heightened fire risk: Aude, Pyrénées-Orientales, Gard, Bouches-du-Rhône, Alpes-de-Haute-Provence and Hérault.

In Var, firefighters have begun simulated wildfire drills to prepare for the peak summer season. Many are volunteers from other regions, training to adapt to the different terrain and wildfire behaviour typical of Mediterranean zones.

Authorities have asked residents and tourists alike to be vigilant and avoid any activities that could ignite dry vegetation, including barbecues, smoking near wooded areas, or using power tools outside.

The heightened fire risk comes as many parts of France have seen water restrictions introduced in recent weeks to combat the growing drought.

Read more: Checks, fines, help: rules for clearing undergrowth around French home

Local authorities respond to heat

Local authorities have announced emergency measures to help people cope with the heat. Check with your mairie for local information, which in many cases is posted to their website.

In Marseille, entry to all public swimming pools will be free of charge for the duration of the heat alert. The city has also opened public gardens until 21:00 and designated numerous “cool spaces” in libraries and local administrative buildings.

Tours has announced the closure of all schools on Monday and Tuesday afternoons due to high temperatures. 

In Vaucluse, the towns of Le Thor and Cavaillon have taken similar steps for primary and nursery schools.

Read more: Surge in private swimming pool ‘squats’ in France

Mediterranean sea warmer than usual

Surface water temperatures are 4C to 5C above average for late June. 

At Juan-les-Pins (Alpes-Maritimes), satellite data confirmed values of 24C to 25C - significantly higher than normal.

This reduces the sea’s natural capacity to regulate surrounding temperatures, particularly at night, contributing to continued heat stress on land.

Impact on glaciers 

The heatwave is also affecting France’s mountain regions. 

The ‘isotherm zero’ - the altitude at which air temperature drops to 0C - has been measured at an unprecedented 5,400m above sea level above Corsica. This level is typically far lower in June.

Glaciologists warn that such conditions accelerate the melting of glaciers and thawing of permafrost in the Alps, increasing the likelihood of Alpine landslides

This link was made manifest on May 28 with the collapse of the Birch glacier in Switzerland, which provoked a landslide that destroyed 90% of the village of Blatten.

While experts do not suggest that this is likely in France, a total of 947 infrastructure points in the French Alps, including ski lifts and power pylons, are built on permafrost that is at risk during periods of heat and may be at increased structural risk during sustained heat events.