If you’re hoping to get lost in the rain on your romantic getaway, take a look at these details about year-round temperatures in Siliguri: The hottest months are usually April and May, with an average temperature of 26°C, while the coldest months are January and December, with an average of 19°C. The rainiest months in Siliguri are July, June, August and September, with each month seeing an average of 724 mm of rainfall.