Sikkim, the eight state of Northeast India. Train connectivity is available till New Jalpaiguri while Air connectivity is available till Bagdogra airport from where one has to travel by road (jeep, travellers) to the state of Sikkim.
If you want to witness snowfall be sure to visit by the end of October. Lachung, Yumthang are the best places to witness snowfall.
You may also visit Sikkim during the month of March - April when the Yumthang Valley is found filled with colorful blooming flowers.