Question

Why is July rainier in Mumbai than in Thiruvananthapuram ?

Answer 1

because monsoon winds blowing from sea first makes landfall at these places.

Answer 2

Bombay is an island and nearly the end of the western ghats. Being an island, it is always hot and humid. Moreover it is closer to the Rajasthan deserts on one side, Vidhyas(Deccan Plateau in the South, it become rain catchment area. Since during July the Southern tip of South West Monsoon moves Eastwards and Northern tip moves towards west, Mumbai gets more rain, particularly between later half of July and the first half of August.