Tourist seasons of Nepal

From beginning of September to till late December and from late February to till late May of are considered the best time of the year to visit Nepal. 

But for the tour and lower part of trekking would be possible to visit in Nepal whole year. The main Nepal’s biggest festivals of Dashain and Tihar (greatest Hindu festivals) fall during October/November months. The sky will remain clear and pleasant temperature. From beginning of 

February- late May are also best times for travel in lower part of Nepal, as you will see colorful flowers and rhododendron bloom during the spring season. Late May to until September is the monsoon season in Nepal but during this time it's better to visit westerns part of Nepal where there is less rain and desert, Upper Mustang and Dolpo.