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 Turrialba: The hottest months are usually April and March, with an average temperature of 19°C, while the coldest months are January and February, with an average of 18°C. The rainiest months in Turrialba are October, June, August and September, with each month seeing an average of 599 mm of rainfall.