Geographically speaking Monsoon winds dont change direction at all.Its the pressure belts of earth that shift Northward in March to may season and the entire wind system shifts northwards. 1. read more
Because temperature of the landmass changes. Temperature is inversely related to pressure and hence, monsoon winds change their direction after six months. For example, during winter, when temperature of landmass decreases and water body becomes warmer, High pressure belt develop over land and low pressure over water body. read more
becoes bobo The Coriolis Force is the reason for this (which as mentioned above is subsequent to the rotation of the earth).. read more