Every year we do multiple trips to Sikkim, and have explored it thoroughly. So we do know exactly how it is every month.
The best time to visit North Sikkim is in April and May, and September to October end. In April, there is enough snow in North Sikkim (Lachen and Lachung) for it to look like a fairyland. However unlike March where trips to Lake Gurudongmar get cancelled many times because of excessive snow, that won’t be the case in April. In May, there won’t be snow in North Sikkim, but the weather is more pleasant, the days are sunny but chilly and its perfect to see lake Gurudongmar. Both April and May, Gurudongmar will be full frozen.
Temperatures are around 12-14 degrees in the day, and in single digits at night, in this season.
In September and October, the monsoon has just ended. This is when North Sikkim’s flora is at its most beautiful. Everything looks very alive and stunningly colourful. The Teesta river and all the enroute waterfalls are deliciously full.
Lake Gurudongmar is at its bluest in these two months, arguably even bluer than Lake Pangong in Ladakhj
In this season, the temperatures range from 16 – 20 degrees in the day, and around 8-10 degrees at night.
July to August end, there is heavy downpour almost daily, and roads in these mountains will be prone to landslides and could be risky to travel. Even the sightseeing would get affected, because it would be very misty.
From November to December, there won’t be rain, so it would be easy to move around. However, rivers and waterfalls have very less water, More importantly Gurudongmar starts to freeze around November, but its neither fully frozen, nor blue, so you don’t see it at its best. You can see quite a lot of stars in the night sky during this period.
Since its the north east, it will become quite dark by 5 pm in the winter months.
From mid December to early March, there is a lot of snow, and sightseeing can get affected because roads might get blocked from time to time.
Click here to read about Goechala Trek in Sikkim!