If you’re looking forward to lots of outings with your partner, take a look at these details about year-round temperatures in Nainital: The hottest months are usually June and May, with an average temperature of 22°C, while the coldest months are January and December, with an average of 11°C. The rainiest months in Nainital are July, August, September and June, with each month seeing an average of 578 mm of rainfall.