Nepal basically has four climactic seasons, namely: summer (from June to August), autumn (from September to November), winter (from December to February), and spring (from March to May). Having a fairly predictable weather, Nepalese monsoons approximately begin from the end of June until the middle of September wherein approximately 80% of all the rainfall accounts within this period leaving the remainder of the year dry. The most pleasant seasons in Nepal are spring and autumn, while high levels of snowfall and freezing temperatures feature the winter season.
Considering the difference in elevation in the regions of Nepal, summer and late spring temperatures range from 28ºC (83ºF) in the hill regions to more than 40ºC (104ºF) in the Terai. Residents and visitors alike brace a much colder temperature ranging from 7ºC (45ºF) to a mild 23ºC (74ºF). Whereas those who find themselves in the central valleys of Nepal experience a minimum temperature of below freezing point up to a chilly 12ºC (54ºF) maximum.
At an altitude of 1,310m or 4,297ft, the Kathmandu Valley offers a milder climate which ranges from 19-27ºC (67-81ºF) in summer to s a 2-20ºC (36-68ºF) in winter.
Greatly affecting the variance in climate, temperature and rainfall is the remarkable differences in altitude of the regions within Nepal within such a short north-south distance. Five climatic zones in Nepal have been identified by the scholar Sharad Singh Negi based on altitude. For areas below 1,200 meters, mainly tropical and subtropical climates prevail. A more cool and temperate climate is predominant in regions whose altitude range from 1,200 up to 2,400 meters. A much colder climate or “cold zone” should be expected in regions with altitudes from 2,400 up to 3,600 meters. Regions whose altitude is from 3,600 up to 4,400 meters fall within the subarctic zone, while the arctic zone covers the regions beyond 4,400 meters in altitude.