Mont Fort

On Saturday, the weather will be unstable and very changeable, alternating between numerous clouds, clear spells and a few scattered showers, mainly in the mountains. Very limited activity in central and upper Valais, and more widespread showers in Chablais, with a few thunderclaps possible. Windy and unseasonably warm. Temperatures forecast for the Rhône plain: lows 15 to 17°, highs 22 to 24°. In stations around 1500m: lows 10 to 12°, highs 15 to 17°. On summits: 8/11° at 2000m, 1/3° at 3000m. Isotherm of 0°: 3400m. Breezy conditions on the plains and in the valleys, moderate to strong south-westerly in the high mountains.

On Sunday, many residual clouds and last showers at first in the mountains, then a change to fairly to very sunny weather. Cloud banks will remain more widespread over the Chablais hills. Temperatures fairly cool for the season, with highs of 21 to 23 degrees on the plains and 13 to 15 degrees around 1500m altitude. Whit Monday, sunny in all regions, with a few harmless cumulus clouds over the higher elevations. Temperatures cool at dawn, then relatively milder during the day, with highs of 22 to 24 degrees on the plains and 16 to 18 degrees around 1500m altitude. Tuesday will be a very fine, sunny day in all regions, with often cloudless skies. Cool temperatures at dawn, followed by a marked easing during the day, with highs of 27 to 29 degrees in the lowlands and 20 to 22 degrees around 1500m altitude. From Wednesday to Friday, calm, sunny and very hot conditions, with highs sometimes exceeding 30 degrees in the lowlands and still 23 to 25 degrees around 1500m altitude. A few isolated thunderstorms are possible in the highlands (to be confirmed). Next weekend could be sunny with summer temperatures, but with a risk of thunderstorms.