Heatwave: The Breton exception myth is burning this week


Weather is improving and Brittany will experience an extraordinary heatwave over the weekend. Monthly records will sometimes be shattered by a few degrees, and Brittany’s temperature record of 41.0°C at Guer (56) and Ancenis (44) during the 2003 heat wave could be improved. Explanations on the scenario predicted this week.

Hot weather arrives on Wednesday

A cold fall is slowly positioning itself over Portugal. It pushes very hot air over Western Europe. The 30°C mark must not be exceeded before Wednesday. For this day, we expect temperatures between 22 and 33°C from Saint-Brieuc to Nantes. The canal shores are kept away by the sea wind, which prevails over the air mass. The hot air channel that reached us on Thursday is intensifying and the heat is spreading all over the region, except for the English Channel beaches and the still-protected islands. 30°C is easily exceeded in Quimper, Pontivy, Rennes, Vannes, Saint-Nazaire or Nantes. Temperatures still remain fairly mild at night, allowing high temperatures to have a limited effect during these two days.

The myth of the “Breton exception” then collapses!

Temperatures have been rising since Friday. They are reaching unprecedented levels for June in our five departments. Monthly precipitation is recorded and sometimes improves by several degrees. Intense heat does not separate any partition. The cooler sea allows the islands to maintain more breathable conditions. Elsewhere, temperatures are systematically above 35°C. In Nantes, the highest temperature was announced with 40°C. For Brest, for example, this could be one of the hottest days since meteorological readings began at this station. The extraordinarily hot weather should continue into Saturday. We’re still looking at 35-40°C in most of the region. The cold drop may approach and the clouds may be higher on the Atlantic coast than the previous day. Temperatures will be less intense than the previous day between the Iroise Sea and the Atlantic coast. Moreover, records are falling again and even the temperature record of Guer (56) and Ancenis (44) on 9 and 10 August 2003 seems possible to be broken! For these two stations it was 41.0°C at the time. This meteorological situation shows us that Brittany is not a shelter from extreme heat events.

The weather trend is very uncertain from then on Sunday. Two scenarios are not shared for now. The first is the return of storms from the Atlantic coast. They allow heat to be dissipated and temperatures to be much more reasonable. The second is the continuation of dry and hot weather and the continuation of strong heat despite the expected peak on Friday and Saturday.

We’re not talking about a heatwave at the moment because the thresholds set for three consecutive days and three nights have to be crossed. The trend is not clear enough yet.

Caution is recommended for the next few days. Remember to keep yourself well hydrated and wait for this exceptional warmth to open your accommodation early in the day. Limit sports activities during the episode and remember to talk to the most vulnerable people.