Northeast India has a subtropical climate that is influenced by its relief and influences from the southwest and northeast monsoons. The Himalayas to the north, the Meghalaya plateau to the south and the hills of Nagaland, Mizoram and Manipur to the east influences the climate. Since monsoon winds originating from the Bay of Bengal move northeast, these mountains force the moist winds upwards, causing them to cool adiabatically and condense into clouds, releasing heavy precipitation on these slopes. It is the rainiest region in the country, with many places receiving an average annual precipitation of , which is mostly concentrated in summer during the monsoon season. Cherrapunji, located on the Meghalaya plateau is one of the rainiest place in the world with an annual precipitation of . Temperatures are moderate in the Brahmaputra and Barak valley river plains which decreases with altitude in the hilly areas. At the highest altitudes, there is permanent snow cover. In general, the region has 3 seasons: Winter, Summer, and rainy season in which the rainy season coincides with the summer months much like the rest of India. Winter is from early November until mid March while summer is from mid-April to mid-October.