If you're hoping to get lost in the rain on your romantic getaway, take a look at these details about year-round temperatures in Koidu: The hottest months are usually February and March, with an average temperature of 27°C, while the coldest months are December and January, with an average of 24°C. The rainiest months in Koidu are September, August, July and October, with each month seeing an average of 505 mm of rainfall.