The months of April, May, October, and November are ideal to plan a trip to Kasol. The best season to visit Kasol is summers as the pleasant weather of the hill village making the place more serene and the liveliness just being perfect for a tour to a village in Kullu district.
Anytime and everytime is the best time!!
in summers you will beat the heat while in winters you will love the chills and about monsoons, you will see the best greeneries. Considering safety monsoon might not be considered as the best time but looking at the climate change i don't think not expecting rains in winters or summers is thing these days!