Records till now show this Manaslu circuit trek has been busiest during October and it's not as active as the commercial Annapurna circuit or Everest. However, April to mid-June during spring and September to November during autumn is the best time to trek when the view of the world's 8th highest peak, its neighboring mountains, beautiful gorges, and startling landscapes are at its best state. Doing/starting this trek as early as December is still fine. We don't encourage do to this trek in late Dec, Jan and Feb. Doing it in mid-winter could be pretty complicated because most of the settlements before and after the Larke La pass may be vacant as people tend to leave their lodges and head out further to a lower elevation due to the fear of increasing chill factor, fewer visitors and possibility of heavy snow.