Question

Why are the north east trade winds dry

Answer 1

north east trade winds r dry because they precipitate in north side of India and when they come to Tamil Nada they are dry

Answer 2

As the name itself addresses to its prospect,  the north eastern trade winds travel a long way from the north eastern side of the continent and acquire the adequately sufficient moisture in order to precipitate.  These winds generally travel towards the southern part of the continent.  So by the time they reach the southern zenith they become anhydrous and already run out of the moisture due to which they are incapable of drenching areas of the south and are hence referred to as dry.