Due to Nepal’s extensive range of geography, the country’s climate varies riotously from one region to the next. As you rise in altitude the temperatures drop and the rainfall increases. The Tibetan Plateau hardly ever breaks the freezing mark, but the tropical lowlands enjoy mild weather most of the year. All through Nepal, however, there are four diverse seasons. The major windows for consistently good weather are spring and autumn. March to April and October to November fetch sunny days, warm temperatures and little rain. This is the peak season for mountaineering the Himalayas.
From November through March, the mercury frequently drops to freezing at night. Mountain passes are snowed in, although Kathmandu and Pokhara rarely get any snowfall. May and June are the hottest and most sultry months of the year, and the monsoon rains from May to September make conditions mucky and unpleasant all through most of Nepal. The mid-land regions are enjoyable more or less all the year round, even though winter nights are cool. The northern mountain region, around an elevation above 3,300m has an alpine climate with significantly lower temperature in winter as can be expected. Depending on the month, visitors should be sure to bring suitable clothing.