Trekking in Nepal can be undertaken and done throughout the whole year. The traditional trekking season in Nepal is from September to November and March to May. There are two major factors to decide when to Trek to Nepal. During the high tourist season in October and November, the flights and hotels are fully booked and horrendously busy. There are four distinct trekking seasons in Nepal. Each season has its distinct attraction to offer. The seasons are classified as follows:
AUTUMN SEASON (September-November)
This season offers excellent weather and tantalizing mountain views. Temperature is moderate, making it a good time for any trekking. The sky is generally clear with outstanding views. Occasionally short storms may dump considerable snow at high altitudes. This season is considered as the best trekking season for the trekking in Nepal. September, October and November are fall in this trekking season in Nepal.
WINTER SEASON (December-February)
The winter season in Nepal is usually snow fall in the higher elevations with risk winds and colder temperatures. Hence is ideal for trekking in the lower elevation. If you are looking for suitable and incredible scenery, this is a great time to Trek in lower elevations. But it is depend upon the weather conditions. Generally, the days are clear in winter season in Nepal. December, January and February months are fall in this trekking season in Nepal.
SPRING SEASON (March-May)
Spring season in Nepal is also considered as the best season to do the trekking and mountain climbing. In this season offers different varieties of wild flora blossoming of the giant rhododendrons above 3000m and hunting paradise during this season, which makes higher altitude trekking more comfortable and interesting. It is mildly warm at lower elevations and quite moderate temperature at higher elevation over 4000m, which provides spectacular and excellent mountains View. March, April and May months are fall in this trekking season in Nepal.
SUMMER SEASON (June-August)
Summer season in Nepal is monsoon with heavy rainfall which makes trekking conditions unfavorable. This season is ideal time for Trekking and tour to Tibet and Tibet. However, in some Trekking regions of Nepal connecting to Tibet and desert parts of Nepal i.e. Mustang, Nar-Phu valley and Dolpo regions are best season to do trekking which is summer trekking a great alternative. The Annapurna region in north-central Nepal also receives significantly less rain than other parts of the country during the summer months and low-altitude, short treks in this region are recommended. June, July and August months are fall in this trekking season in Nepal.
October and November are the most popular trekking months in Nepal. During this time, chances are high for clear skies and great mountain views. The nights are usually cold in the mountains, but the bright sun makes for pleasant day temperatures (above 20s° C, falling to 5° C at night between 1,000 m and 3,500 m). At higher altitudes temperatures range from about 15 ° C- 20° C during day time to -10° C at night. Mornings are usually clear with clouds building up during the afternoon, disappearing at night to reveal spectacular starry skies.
December, January and February are good for trekking as long as you stay below 3,000 m. Above 3,000 meters it gets very cold, and trails are often covered with snow. It is usually about 10 degrees colder than in autumn. High passes (above 4,000 m) are generally closed from Mid-November to Mid-March.
March and April is a good time for trekking too. The sky is a bit dustier, but you normally get good views in the mountains. With Rhododendron, Nepal’s national flower, being in full bloom, walking through the forests is particularly nice.
May is also rather good for trekking, although it can get quite hot in lower altitudes and there is a higher chance of rain.
During the monsoon from June to August, trekking is not very popular due to the heavy and frequent rain showers. However, the vegetation becomes very green and lush, which makes for beautiful sceneries. In Upper Mustang, Humla and Dolpa, summer is an excellent time for trekking! These areas lie in the rain shadow of the main Himalayan range and are therefore not affected by the monsoon. Getting there might be a challenge though due to unpredictable weather conditions in the Lowlands, which generally affect flight schedules.