why do mountains affect weather

 Mountains:

There are two sides: wayward and leeward.

Wayward: Whenever it is raining, the wayward side gets the rain so there is good soil most of the time. But as the cloud goes up the mountain, it keeps raining until soon there is no more water in the cloud.

Leeward: Now the cloud is at the other side of the mountain. There is no more precipitation so the leeward side of the mountain gets no rain so the flat ground on this side of the mountain is dry and humid.