Planning for the weather is an important factor for making your trip to Cabo Frio a success, especially when you're splurging. 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.