It’s possible to trek in Nepal throughout the year, whereas climbing is slightly more seasonal.
There are four seasons in Nepal and each has its distinct features.
The temperature is mild at lower elevations and moderate or cool at higher elevations. The view of the majestic Himalayan range is breathtaking; however there may be sporadic snowfall at high altitudes. Spring is one of the best seasons for trekking and climbing.
Trekking in the summer or the monsoon period will be affected by rain, but could be a boon for the keen botanist as the higher valleys and meadows blossom with flowers and lush vegetation. Trekking in rain-shadow regions (places that are out of reach of the rain clouds because of the high mountains) north of the Himalaya like Upper Mustang and Dolpo could be an ideal trek selection. Rain isn’t constant in these months; but it is certain and regular.
This season is considered the best time for trekking in Nepal, offering excellent weather and mesmerizing mountain views. Moderate temperature and clear sky make this a great time to do any of our treks or climbs.
Winter is also good for trekking, the only issue naturally being the cold.
There is occasional snowfall at higher elevations and it gets colder at night, but the days are clear with blue sky and relatively few trekkers on the trail. However you need to be selective in choosing winter trekking routes, as climbing and crossing high passes won’t be an ideal option. Treks like Everest base camp, Annapurna Sanctuary, etc can be done even in winter and as they are well provided with tea houses and logistics these are good options for winter treks.