1) Autumn (September - November)
Autumn season is considered to be the best time for trekking in Nepal especially in the Himalayas, during the season, it offers an excellent weather and exciting mountain views. The biggest festivals of Hindu--Dashain and Tihar also fall in this season. Generally is clear and the temperature is moderate, which make good time for having trekking or for holidaying.
(II) Winter (December - February)
Winter season is well-known for occasional snowfall especially at the higher elevation. Thus the trekking is suitable at lower elevation especially below 3000m, such as short trekking around Ghorepani Poon, Everest view trekking, Royal Trekking to name a few.
(III) Spring (March-May)
Spring season is also considered to be the best time for trekking in Nepal especially in the Himalayas. During the season, it is quite warm at higher elevations as well and little hot at lower elevations. Temperature is quite moderate. It suits to for peak climbing during the season it is possible to have trekking above 3500 m, different varieties of wildflowers blossom during this season, such as Rhododendron and we can have fantastic views of the snow capped mountains.
(IV) Summer/Monsoon (June - August)
Summer season also called monsoon season in Nepal. During this season, it rains almost every day. This is perfect time in order to capture the photographs thus it suits for photographers and nature lovers also in high Himalayas. It is recommended that for those who arrange trekking during this season needs to carry insect sickening medicine. But, it is the perfect time to have trekking around Upper Mustang, upper Dolpo and Manaslu areas, as it does not rain in the areas.