Nepal's climate, influenced by elevation as well as by its location in a subtropical latitude, ranges from subtropical monsoon conditions in the Tarai, through a warm temperate climate between 4,000 and 7,000 feet in the mid-mountain region, to cool temperate conditions in the higher parts of mountains between 7,000 and 11,000 feet, to an Alpine climate at altitudes between 14,000 and 16,000 feet along the lower slopes of the Himalaya mountains. At altitudes above 16,000 feet the temperature is always below freezing and the surface covered by snow and ice. Rainfall is ample in the eastern portion of the Tarai (which receives from 70 to 75 inches [1,800 to 1,900 millimetres] a year at Biratnagar) and in the mountains, but the western portion of Nepal (where from 30 to 35 inches a year fall at Mahendranagar) is drier.

In Kathmandu Valley, average temperatures range from 50° F (10° C) in January to 78° F (26° C) in July, and the lowest and highest temperatures recorded have been 27° and 99° F (-3° and 37° C). The average annual rainfall is about 55 inches, most of which falls in the period from June to September. At Pokhara the temperature ranges from 40° F (4° C) in January to approximately 100° F (38° C) in June, just before the monsoon. In winter, temperatures during the day rise to 70° F (21° C), creating pleasant conditions, with cool nights and warm days. Because warm rain-bearing monsoon winds discharge most of their moisture as they encounter the Annapurna range, rainfall is quite heavy (about 100 inches) in the Pokhara Valley.

The climate of Nepal is best assessed with the climate at 4 distinct places. These are Kathmandu valley, Pokhara valley (West), Chitwan (Terai), and Namche Bazar (East & High mountain).