Clouds and precipitation form on the windward side of the mountain due to change in temperature and pressure.
What is the relation between pressure and temperature?
Temperature of any substance is directly proportional to the pressure of that substance.
If the temperature of the wind increases so that winds get warmer and at the same time pressure of gas also increases, due to which particles will go far from each other. After this warm air rises up and cools down will condenses to form clouds, after this precipitate will falls on the windward side of the mountain.
Hence due to temperature and pressure precipitate will form on the windward side of the mountain.
