If you’re looking forward to lots of outings with your partner, take a look at these details about year-round temperatures in Sen Monorom: The hottest months are usually April and March, with an average temperature of 26°C, while the coldest months are January and February, with an average of 23°C. The rainiest months in Sen Monorom are September, July, August and October, with each month seeing an average of 249 mm of rainfall.