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 Cabo Frio: The hottest months are usually February and March, with an average temperature of 25°C, while the coldest months are July and August, with an average of 22°C. The rainiest months in Cabo Frio are November, December, January and March, with each month seeing an average of 191 mm of rainfall.