Heavy snowfall was reported from Sandakphu in West Bengal's Darjeeling district and Nathu La, Tsomgo and Juluk of Sikkim on Wednesday.
Due to the weather condition in Sikkim, tourist vehicles did not venture out to spots like Tsomgo and Baba Mandir in East Sikkim district, police said.
The decision was taken as the road to Tsomgo was shut due to snowfall and to prevent accidents.
The Sikkim weather office forecast more snowfall and dense fog in the upper reaches of the hills over the next three days.
Visibility will go down to below 100 metres in the northern West Bengal districts also due to fog over the next three days.
Since Wednesday morning, vast stretches of Darjeeling district including Sukhiapokhri, Lodama and Jorebungalow were wrapped in a thick veil of fog.
Siliguri and Darjeeling towns, as also large parts of Sikkim, experienced heavy rain between Tuesday evening and Wednesday morning.