Nepal’s climate is influenced by many factors such as latitude, prevailing winds, oceanic distance, and position of mountains. It ranges from tropical to alpine depending upon the altitude. The terai region which lies in the tropical southern part of the country, for instance, has a hot & humid climate. The mid-land regions are pleasant almost all year around although winter nights are cool. The northern mountain region, around an altitude above 3353 m has an alpine climate with a considerably lower temperature in winter as can be expected.
Nepal has four major seasons
Winter (December-February), Spring (March-May), Summer (June-August), Autumn (September-November)
On the basis of seasonal change in climatic conditions, the climate of Nepal can be divided into four major seasons - Winter (December-February), Spring (March-May), Summer/Rainy (June-August), Autumn (September-November)
The main feature of each season is described below.
Winter Season ( December-February)
It includes the month of December, January and February. During winter season, the sun shines over the southern hemisphere and the temperature becomes very low all over the country. It is about 10 o C temperature in the Terai. The Himalayan zone above 3000m, records the temperature below freezing point. The higher mountain areas are quite cold. On the whole, winter is generally a dry season. The monsoons blow from land to the sea during this season. However, westerly wind cause light rain in the western Nepal. Clear sky, foggy or frosty and cold morning are the general features of this season.
Spring Season (March – May)
The temperature is mildly warm in low lands while moderate in higher altitudes with plenty of opportunities to have tryst with the mountain views. It is also the time for flowers to blossom particularly- the national flower of Nepal ' rhododendron' sweeps the ascending altitudes with its magnanimous color and beauty.
Summer/Rainy Season (June-August)
The hot weather season begins in June and continues till the end of August. Due to the northward march of the Sun, the high temperature occurs in all parts of the country. During this season, temperature exceeds 35 o C in the Terai. Towards North, altitude increases and it remains warm in midland hills and valleys. It is cool in the Himalayan region. Days become sunny, windy and dusty and it gets hazy in some areas. Most parts of Nepal are dry in this season. However, because of great heat, precipitation in the form of rain and sleet occasionally occurs from local convective storms in April and May.
During this season, monsoon blows from south-east direction and bring rain to the country. The regional distribution of rainfall varies from one to the other area. It depends on the oceanic distance and local topographic features of the place. Pokhara Valley located in the central Nepal receives more than 400 cm rainfall. Similarly, southern slopes of Mahabharat and Churia hills in East Nepal receive more than 200 cm rainfall. In general, rain diminishes from Pokhara Valley towards west and north. In the north, there exists a larger rain shadow area beyond the great Himalayan Ranges in the central and western parts of Nepal . It receives poor rainfall less than 50cm. During rainy season, it gets sultry and humid. Temperature slightly drops down in rainy season due to frequent rainfall.
Autumn Season (September – November)
This is the best tourist season in Nepal with the summer gone by and the winter to set in. The weather is highly pleasant so are the mountain views. This is the peak season for trekking as mountain views are guaranteed so better book your flight in advance. This is also the season of festivities as Nepal celebrates the biggest Hindu festivals Dashain followed by Tihar