Climatic conditions of Nepal vary from one place to another accordinmg to the geographical features. In the north, summers are cool while the winters severe, while in south summers are tropical and winters are mild. There are basically five major seasons in Nepal: spring, summer, monsoon, autumn and winter. An average temperature drop of 6°C occurs for every 1,000 m gain in altitude. In the Terai, summer temperature exceeds 37° C and higher in some areas while the winter temperatures range from 7°C to 23°C in the Terai. In mountainous regions, hills and the valleys, summers are temperate while winter temperatures can come down under sub zero. The valley of Kathmandu has a pleasant climate with average summer and winter temperatures of 19°C – 35°C and 2°C – 12°C respectively.
The Himalayas act as a barrier to the cold winds blowing from Central Asia in winter, and forms the northern boundary of the monsoon wind patterns. Eighty percent of the precipitation is received during the monsoon while falls in June-September. Winter rains are more pronounced in the western hills. The average annual rainfall is 1,600 mm, but it varies by eco-climatic zones, such as 3,345 mm in Pokhara and below 300 mm in Mustang. An interesting fact is that there is no seasonal constraint while traveling in and around Nepal. Even in December and January, when winter is at its peak, there are compensating bright sun days in between. As with most of the trekking areas in Nepal, the best time for visit is during spring and autumn. Spring is the time when rhododendrons bloom while the clearest skies are found after the monsoon in October and November. However, Nepal can be visited the whole year round.
Here’s a brief view of the average temperatures and rainfall during peak summer and winter in three most popular tourist areas:
||Summer (May, June, July)
||Winter (Dec, Jan, Feb)