The leeward side of the Rocky Mountains typically experiences an arid or semi-arid climate due to the rain shadow effect.

The leeward side of the Rocky Mountains is known for an arid or semi-arid climate due to the rain shadow effect. As moist air from the Pacific Ocean is forced upward by the mountains, it cools and releases precipitation on the windward side. By the time the air descends on the leeward side, it is dry and warms up, causing a significant decrease in rainfall. This dry air leads to arid or semi-arid conditions, characterized by low humidity, limited rainfall, and landscapes with desert-like features, making the region much drier than the windward side.