Autumn (September to November)
This is the best season to visit Nepal. The weather is clear, cool, and perfect for trekking, sightseeing, and enjoying mountain views. It is also festival season in Nepal.

Spring (March to May)
Spring is warm and beautiful with blooming flowers. It is a great time for trekking, jungle activities, and cultural tours.

Winter (December to February)
Winter is cold, especially in the mountains, but good for low-altitude tours. Sightseeing in Kathmandu, Pokhara, Chitwan, and Lumbini is comfortable.

Monsoon (June to August)
Monsoon brings rain but makes the landscape green and fresh. Some places like Mustang, Dolpo, and Rara are perfect to visit during this season because they remain dry.

Summary
Trekking is best in autumn and spring. City tours can be done all year. Jungle safaris are best in autumn, winter, and spring. Mustang, Tibet, and Kailash are best during summer.