Although trekking in Nepal can be organized throughout the year, October through May are considered to be the best months for trekking. Summer months of the year which coincides with monsoon begins in mid-June and drains in mid-September making travel wet and warm. The mountain views may not be at their best as rain clouds and haze over hang the mountains occasionally obscuring the enchanting views. These times are blessed for the keen botanist as the higher valleys and meadows blossom with flowers and lush vegetation. During monsoon it does not mean that it will rain every day. Besides, some of the most frequented trails will not be crowded and some people like it that way. It can actually be enjoyed in the upper part of the Annapurna circuit around Marfa, Jomsom and Muktinath as the monsoon does not get in this trans- Himalayan area.
Note :- It is recommended to carry insect repellent when trekking during summer months.

Autumn being the best season for trekking, affronts excellent weather and tantalizing mountain views January and February are noted for cold weather with occasional snowfall at higher elevations. Again, excellent views are common. These months are popular and ideal for trekking for those who are well equipped or who remain at lower elevations below 3,000 meters.

Late February brings spring in Nepal and offers exhilarating trekking for those who are interested in flowers, birds and natural grandeur. Different varieties of wild flowers, specially the rhododendrons make the hill side above 8,000 ft haunting paradise during this season.

April and May are the expedition season and the best time for climbing the high peaks . It is mildly warm at lower elevations but occasional haze mars beautiful view of mountains. At higher elevations over 4,000 meters the mountain views are excellent and the temperature is quite moderate even at night.