The best time to visit West Bengal is October to March
October-March is relatively less humid and is the time of the 10 day Durga puja festival. Sunderbans is also opened at this time for visitors. In summers the temp goes to 38 degrees, and the humidity levels are very high. In winters the temperatures may fall to 10 degrees. Teesta Tea and Tourism Festival is held in November.
The hilly areas of Darjeeling and Kalimpong is best visited from March to June. June to August is the rainy season here.