France weather update: highs of up to 35C next week as high-pressure system returns

France is set for yet another burst of hot weather at the start of next week, with highs of up to 35C in the south-west and 30C across several areas of the south. 

The renewed bout of unusually warm weather will be caused by the return of a high-pressure anticyclone over much of France.

It will last until at least the middle of next week (September 23), although above-average temperatures are possible until next weekend (September 26/27).

The calm conditions will also prevent any significant rainfall, further adding to France’s drought woes and almost certainly seeing drought restrictions extended further into autumn. 

It comes after a September heatwave racked France at the start of the month, breaking monthly heat records.

Return of high-pressure system

France saw a powerful high-pressure anticyclone cover the country at the start of the week, bringing temperatures of up to 36C in the south-west and well over 30C across much of the south. 

This system is currently retreating south, with clouds and a low-pressure system from the British Isles sweeping in and leading to temperature drops. 

The high-pressure system will return at the weekend however, seeing temperatures steadily increase before another sharp jump on Monday (September 21). 

While it is too far in the future for exact temperature predictions, state forecaster Météo France is forecasting highs of 25C in the north next Wednesday (up to 27C in Paris) and 30C in the south, up to 32C in Bordeaux.

Meteorologist at media outlet Actu Yann Amice predicts temperatures could reach even higher, again reaching 35C in the south-west around Bordeaux. 

Temperatures will drop gradually throughout the rest of the week, but still remain above 20C in the north and 25C in the south until the end of the weekend. 

While this is above seasonal averages, it is not warm enough to trigger heatwave alerts. 

You can find an interactive map showing expected temperatures in your area for up to two weeks on the Météo France website.

Little rain forecast 

The presence of the high-pressure system above France acts almost as a shield, pushing away other weather systems while maintaining calm conditions.

This includes pushing away cloudy skies, and with it the rain they bring. 

Indeed, aside from a few scattered showers across the coastal English Channel, no rain is currently forecast across France until the end of the month. This may change as models progress and conditions change, but is currently the case as of September 16. 

Coming on the back of a fierce summer drought, rainfall is desperately needed to refill France’s underground aquifers and streams. 

A lack of rain will only further deplete these water sources however. 

In the latest report, over 60% of France’s aquifers were below average levels for September, with those in the central-west and east particularly low. 

Mediterranean disturbances

The continuation of unseasonably warm conditions is also having an impact on the Mediterranean. 

Successive heatwaves and higher-than-usual temperatures have kept the waters of the sea much warmer than usual – surface water between Nice and Corsica is currently a balmy 26C - 27C. 

This has a potentially devastating effect on the local ecosystems present in the water, unaccustomed to high temperatures for such long spells. 

Unlike larger bodies of water such as the Atlantic, the Mediterranean struggles to dispel excess heat as it has fewer places for it to escape, being enclosed by landmasses in all directions – many of which are suffering from intense temperatures. 

Higher sea temperatures also have an impact closer to home, as they can increase the strength of already-fierce autumn storms and downpours along the southern coast. 

These storms, which can see weeks worth of rainfall in just a few hours, are actually counterproductive to ending drought conditions. Such conditions see rain fall too quickly and harshly to permeate through soils to refill underground aquifers, and instead pool at surface level, leading to flooding.