The seasons in Nepal are pretty much the same as Europe or opposite of the Australian seasons. In January it’s cold, while in July you could make do with shorts and a T-shirt. The climate of Nepal is moderate which means the winters are dry and the summers are hot. But because of the huge range in altitude and landscape, the climate of Nepal differs significantly throughout the country.
The monsoon happens at approximately the end of June to end of August. About 80 percent of the rain falls during this period. The monsoon effects the entire country. However, the remainder of the year is dry. Spring (March to May) and autumn (September to November) are the most pleasant seasons. Winter (December, January, and February) temperatures drop to freezing with a high level of snowfall in the high mountains.
Summer, monsoon season, and late spring temperatures range from 28ºC (83ºF) in the hill regions to more than 40ºC (104ºF) in the Terai (southern plains). In winter, the average maximum and minimum temperatures in the Terai range from a brisk 7ºC (45ºF) to a mild 23ºC (74ºF). The central valleys experience low temperatures but not often falling bellow freezing and a chilly 12ºC (54ºF) maximum.
The Kathmandu Valley, situated at an altitude of 4,297ft (1,310m), has a mild climate most of the year. Summer temperatures range from 67-81°F (19-27°C), and in winter temperatures are between 36 and 68°F (2-20°C). During the rainy monsoon season between June and August, there is an average rainfall of between 7.8-14.7 inches (200-375mm) in Kathmandu. May and June can be very hot and humid until the monsoon rains bring relief. In spring (March to April) and autumn (October to November) the temperatures are pleasant with occasional short bursts of rain, while November to February are dry, but can be very cold, especially at night.