The best time to visit Gangtok is during spring (March to May) and autumn (October to December). In spring, rhododendrons are in bloom on the hillsides and the air is clear enough for views of Kangchenjunga. Autumn brings similar clarity after the rains and is the season for many Buddhist festivals.
The monsoon (June to September) brings heavy rain and frequent cloud cover — the mountain views disappear for weeks at a time. Winter (January to February) is cold, with occasional snow, and roads to nearby sites like Tsomgo Lake may be temporarily closed.
The Enchey Monastery Chaam festival (masked dancing) takes place in January and is worth timing a visit around. Losar (Tibetan New Year) falls in February or March and is celebrated with great energy across the city.