If you're hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Kasauli: 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.