If you’re looking forward to lots of outings with your partner, check out these details about year-round temperatures in Thirunelly: The hottest months are usually March and February with an average temp of 80°F, while the coldest months are January and December with an average of 78°F. The rainiest months in Thirunelly are July, June, August, and September, with each month seeing an average of 23 inches of rainfall.