If you’re looking forward to lots of outings with your partner, take a look at these details about year-round temperatures in Nallathanniya: The hottest months are usually March and February, with an average temperature of 25°C, while the coldest months are January and February, with an average of 24°C. The rainiest months in Nallathanniya are November, October, May and September, with each month seeing an average of 427 mm of rainfall.