Autumn (Sep – Oct): This season is peak season in Nepal. This season offers excellent views and panoramic mountain range.
Winter (Dec – Feb): This season is off season. Actually on the high elevations would be snowing and more cold.
Spring (March – May): This season is also peak season but not like autumn. Sure, the weather would be clear and bit warmer below the 3000m.
Summer Monsoon (Jun – Aug): Summer monsoon season is starts from the June up to end of August.