Brittany will have finally yielded in the face of the heat wave which has been going up for eight days in the south of France. 30 ° C in Brest, 32 ° C in Rennes, 33 ° C in Lorient … So far spared, the region is experiencing stifling temperatures this Friday. From there to talk about heat wave? “We can say that we are in a heat wave only on a small portion of Brittany,” explains Jérome Dréano, meteorologist at Météo Bretagne.
#Chaleursinense \ ud83c \ udf21 \ ufe0f \ ud83e \ udd75 𝐋𝐚 𝐜𝐚𝐧𝐢𝐜𝐮𝐥𝐞 𝐥𝐚 𝐟𝐚𝐜 𝐟𝐚𝐜̧𝐚𝐝𝐞 𝐨𝐜𝐞 Why𝐚𝐧𝐢𝐪𝐮𝐞
\ UD83D \ Udd38 37 ° C in Clisson & Machecoul
\ UD83D \ Udd38 36 ° C in Nantes & La Baule
\ UD83D \ UDD38 35 ° C in Ancenis & Nort-sur-Erdre
\ ud83d \ udd38 34. C to Vannee & Redon
\ UD83D \ Udd38 33 ° C in Lorient & Rennes
\ UD83D \ Udd38 32 ° C in Audierne & Quimper pic.twitter.com/GHhoIIxaH7– Breton weather (@temps_breton) August 15, 2025
Strong heat thresholds
This name meets strict criteria. Temperatures must exceed regulatory thresholds, specific to each department, on at least two thirds of their surface and for at least three days and three nights in a row.
In Brittany, these thresholds are set at 18 ° C at night and 31 ° C during the day in the Côtes-d’Armor, 19 ° C at night and 32 ° C The day in Finistère and Morbihan, 19 ° C at night and 34 ° C the day in Ille-et-Vilaine.
On the side of Finistère and Morbihan, “we will go beyond the thresholds,” explains Stéven Tual, meteorologist for the Breton Time company. Not easily, but we will exceed them ”.
Hence the orange vigilance decreed by Météo-France in these two departments, where phenomena of “tropical nights” (during which the temperature does not descend within 20 ° C) are expected this Friday and this Saturday evening.
“Rarely affected temperatures” Saturday
“35 ° C are announced on Saturday in the center of Finistère, 34 ° C in Ille-et-Vilaine,” continues Stéven Tual. It is a fairly notable episode for Brittany. Temperatures will approach records, with levels rarely affected between the Crozon peninsula and the Lorient country. »»
Only the Côtes-d’Armor will escape the furnace, thanks to “sea winds” which “will allow temperatures to reach” only “30 ° C, or even less in the Goëlo”, plans the meteorologist.
Fallout from temperatures on Monday
The unusual climatic episode will nevertheless be a passenger. Thunderstorms will indeed take over, on Monday. This “degradation”, for the moment “complicated to predict”, recognizes Stéven Tual, should last until Tuesday. With the consequences of a drop in temperatures, and “a little rain”. What is not bad news for the environment, underlines the meteorologist.