Monsoon winds have sufficiently long trajectories and persist long enough to be influenced by the Coriolis effect such that surface winds are deflected to the right in Northern Hemisphere and to the left in the S. Hemisphere. Monsoon circulation results wet summers and relatively dry winters imposed by insolation, topography, and land and water distribution.
Summer monsoon rains over southern Asia can reach record amounts.
For example, Cherrapunji, India receives an average of 1080 cm of rainfall each year mostly between April and October. Monsoon rainfall is neither uniform nor continuous. The rainy season typically consists of a sequence of active and dormant phases. The weather is cloudy and rainy during a active period, while the weather is hot and dry during a dormant period. The sequence of active and dormant phases is repeated about every 15 to 20 days during the wet season.