Monsoon produces strong seasonal wind, a wet summer and a dry winter. The dry winter monsoon will occurs from September to March. South Asian is dry and hot during winter. The winds from northeast carry little moisture because of losing significant amount of moisture in their path over Asian land mass. The flowing of the cold air on to subcontinent is prevented by Himalayas which acts as a barrier for cold wind and causes high temperature. The direct solar radiation over south Asian land also increases the temperature in winter.  The winds collect some moisture from Bay of Bengal and flow toward peninsula which receives the majority of rainfall in winter. South Asian land surfaces become warmer than surrounding ocean by up to 20 degree C during summer, resulting low pressure systems over the land especially over Tibetan plateau. Hence the southwesterly winds pick up lots of moisture from Indian Ocean, Arabian ocean and Bay of Bengal and cause heavy rainfall over south Asia during June to September