The monsoon of the Indian subcontinent is one of the most predictable weather features in the world. From October through May, the wind blows southward from high pressure over the Himalayan Mountains toward the Indian Ocean. This produces dry weather. During the latter part of the dry season, the air over India gets very hot from increasing summer sun and dry ground.
At some point, usually in June, the air over India becomes hotter than the air over the Indian Ocean, causing a reversal of the wind direction. This moisture-laden southerly wind brings heavy, much-needed rainfall to the Indian subcontinent. During May, just before the monsoon bursts, weather conditions across much of India, Bangladesh, and Pakistan become miserably hot and humid with temperatures in the 100s and dew points in the 80s. The upcoming monsoon will bring cooler temperatures with the rainfall.