Weather patterns over France

A high-pressure system known as an anticyclone has returned to France, bringing calm and dry conditions for much of the week. However, fog and low clouds have developed in several regions, especially during the early morning hours.

Fog-prone regions

Areas in the north, northwest, and parts of the east, including Lille, Rouen, Paris, Metz, and Strasbourg, are experiencing frequent and persistent fog. The valleys of the Saône and Loire rivers, as well as the Sologne region, are also commonly affected by fog.

Formation of fog

Fog develops as the ground cools during longer autumn nights, combined with humid air. Light winds prevent this moisture from dispersing, allowing it to condense into tiny water droplets. High pressure keeps this humid air close to the ground, and the weak October sun is not strong enough to clear the fog quickly.

Impact on visibility and travel

In some areas, visibility has dropped to less than 200 meters, leading to advisories for drivers to reduce speed and use fog lights. For those planning outdoor activities, walking in the afternoon or at higher elevations may offer better visibility and more sunlight.

Temperature differences

There is a noticeable temperature contrast between cloudy and sunny areas, with temperatures ranging from 15 to 19 °C under clouds and 20 to 25 °C in sunlit regions. In the Southwest, temperatures reached as high as 27 to 28 °C on Wednesday and Thursday.