If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Nagaon: The hottest months are usually May and August with an average temp of 81°F, while the coldest months are January and December with an average of 68°F. The rainiest months in Nagaon are July, August, June, and September, with each month seeing an average of 21 inches of rainfall.