The best months are September, October & November during the Autumn season and after mid March, April & May during the spring season are consider as the best seasons for attempting trekking and Climbing. Autumn (mid-September to end-November) is the most popular time to peak climbing in Nepal. Generally during autumn, the weather is clear with mild to warm days and cold nights. However, in the higher altitude, the nights drop into freezing temperature. In this season, the mountains views are astonishingly clear.
Spring and early summer (mid-March through May) the mornings are usually clear but afternoon cloud build-up brings occasional showers. The days are mix up with warm and rain, which displays wildflowers like rhododendrons. The whole country is lush and an abundant green at this season. This period instigate the second most popular and pleasant trekking and climbing season. Late-march into April is especially beautiful. It is also a good time for climbing as the high passes are usually snow free and the mountain views are still clear in April. Up to May, the weather becomes hazy and disturbed with the clouds. The best months has been defined due to their nature of best visibility, best weather condition other then.