Planning for the weather is a good way to make your trip to Thirunelly relaxing and enjoyable, especially when you're splurging. 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.