Climate and Terrain
Rain Shadow Explained: Why One Side of a Mountain Is Wetter
How mountains create rain shadows, why air dries after crossing terrain, and how rain shadows shape deserts, forests, and local climates.
Quick answer: A rain shadow forms when mountains wring moisture out of air on the windward side, leaving drier air on the leeward side.
Windward side
Moist air rises up the mountain, cools, and can produce clouds and precipitation.
This often makes the windward side wetter and greener.
Leeward side
After crossing the crest, air descends, warms, and dries.
That can create drier valleys, deserts, or sharp climate contrasts over short distances.
Weather impacts
Rain shadows influence storm totals, snowpack, agriculture, water supply, and fire risk.
They are a reminder that terrain can dominate local weather.