If you’re looking forward to lots of outings with your partner, take a look at these details about year-round temperatures in Surlej: The hottest months are usually July and August, with an average temperature of 10°C, while the coldest months are January and February, with an average of -7°C. The rainiest months in Surlej are August, May, June and July, with each month seeing an average of 179 mm of rainfall.