France braces for heatwave: 38C expected in Paris and 37C in south-west

Heatwave warnings are set to be raised across France in the coming days, with highs of 38C in Paris and 37C in the south-west expected.

Dry, hot weather has been in place across most of the country since the start of the week. This is predicted to last into next week with steadily rising temperatures and warmer nights. 

Temperatures are set to peak between Friday (June 20) and Sunday (June 22), although on both sides of this remain significantly warmer than average for the season. 

State forecaster Météo France is issuing canicule (heatwave) warnings for several departments in the west and centre of France on Thursday (June 19), which are likely to be expanded in the days after.

Current forecasts for Thursday see heatwave warnings in place from Morbihan (Brittany) to Haute-Garonne (Occitanie), with alerts currently at a tier-two yellow level.

Heatwave warnings may be extended – and rise in alert level – during the weekend, and affect up to three-quarters of France, with all areas except the north-east facing warnings.

Météo France only provides warnings up to a maximum 48 hours in advance, meaning official alerts for the weekend are not yet available. Check its website regularly to see the latest warnings. 

Canicule warnings to extend across most of France

Canicule warnings are different from a standard heatwave (vague de chaleur). 

Heatwave alerts are raised at a national level when temperatures across France reach a certain level, whereas for canicule are based on local factors at departmental level. 

This includes both day- and night-time temperatures, which need to be above a certain level – proportionally higher than seasonal averages for that department – for three days and nights until a warning is raised. 

This is why Thursday is the start of canicule warnings in France despite high temperatures being recorded across much of the south and south-west this week, and why warnings are likely to last for several days as conditions remain warm. 

The prolonged length of high temperatures are seen as dangerous, and as alerts rise in significance, local authorities can enact heatwave plans to allocate more resources to elderly and vulnerable people. 

This can include more assistance at care homes and hospitals, as well as daily checks on vulnerable residents. 

Overnight temperatures set to soar 

One key factor of the incoming heatwave is the high overnight temperatures. 

The risk of ‘tropical nights’ (nuits tropicales), where temperatures do not drop below 20C during the period, will spread to the north over the weekend. 

In some coastal areas of southern France the effect is already underway, with temperatures at 05:00 in the morning reaching close to 25C.

This can be particularly damaging as it prevents both people and properties from cooling down in the evening in preparation for the next day. 

In particular, houses in areas that see cold winter weather – such as Brittany, Normandy, and the north of France – are more at risk as homes are designed to trap heat. 

A few days of high overnight temperatures – areas in the north experience around 20 days per year on average – can make conditions extremely uncomfortable.

Despite homes in the south being more apt for dealing with high temperatures, overnight heat can still cause problems, particularly if they last for prolonged periods without respite.

Nice is the capital for high overnight temperatures, and experienced 61 ‘tropical nights’ in 2024. This could rise to a potential 90 in the coming years due to climate change.

These tropical nights can negatively impact health by preventing the body from properly thermoregulating and cooling down at night, making people more susceptible to heat-related illnesses in the day including heatstroke. 

In addition, they can increase the risk of diseases such as chikungunya, and the risk of forest fires as vegetation is further dried out by persistent high heat.