How does the geographic distributions of monsoonal climate explain why koppens monsoonal climates typically have higher precipitation?

The monsoonal climates are located just north of the Equator, but their formation is above the sea surfaces, not in the mainland, and their influence is mainly on peninsular regions.

Because the formation of the monsoons is above the warm sea waters, there's a very high amount of water vapor in the air, so when those air masses are reaching the land, enormous amounts of rainfall occurs.

Most of the places that have the biggest amounts of precipitation in the world, are places where the monsoons are the most dominant.