Planning for the weather is a good way to make your trip to Kasauli relaxing and enjoyable, especially when you’re splurging. The hottest months are usually June and May with an average temp of 86°F, while the coldest months are January and December with an average of 60°F. The rainiest months in Kasauli are July, August, September, and June, with each month seeing an average of 7 inches of rainfall.