Though trekking is possible throughout the year in Nepal but the trekking season in Nepal is March-May (Spring) and September-November (Autumn). During these seasons, the weather is fine with clear skies. One can go for moderate to challenging trekking in Nepal during these months. Popular treks in Nepal include Everest Base Camp, Everest three passes trek, Annapurna Base Camp, Annapurna Circuit, Langtang Valley trek, Ghorepani Poon hill trek etc.
Spring trek season (March-May)
Spring is another great trek season in Nepal besides the high trek season in Nepal from October and November. Spring will be warmer and more comfortable in high altitudes. During April and May, some treks will give you beautiful rhododendrons in full blossom. Spring is also the popular season for climbers to scale Nepal’s +8,000 meters peaks.
Summer trek season (End June-Mid Sep)
While trek in Nepal during summer is still possible but is not good due to monsoon starting from June till another two months. It will be too wet for a trek with muddy and leech-infested trails. But it’s possible to trek at the trans-Himalayan regions like Upper Mustang and Manaslu areas which receive less rainfall.
Fall Autumn trek season (Mid Sep-Nov end)
The best trekking season in Nepal is the fall Autumn season. The weather will be clear with clear skies and with monsoon clearing off around July. September will still be warmer and with no snow below 4,000 meters. But December will be much colder. Quite a number of trekkers visit Nepal from all over for treks in Nepal during autumn.
Winter trek season (End Nov-mid Feb)
Trekking in Nepal in winter will be much colder with the weather likely to be with blue sky and sun. But trekking no doubt is possible with warm clothing. High passes can be blocked by snow at high altitudes.