Föhn effect

The Föhn effect occurs when moist air is forced to rise over a mountain range. As it ascends, the air cools and releases moisture as rain or snow. When the air descends on the leeward side, it warms up and dries out, causing the weather there to be clear, warm, and dry—despite recent precipitation on the windward side. This process explains why some mountain regions have lush windward slopes and dry, warm leeward slopes. Essentially, the Föhn effect is a mountain-driven weather pattern that influences local climate by shifting moisture and temperature across terrain.