Planning for the weather is an important factor for making your trip to Serra Negra a success, especially when you’re splurging. The hottest months are usually September and October, with an average temperature of 22°C, while the coldest months are July and June, with an average of 18°C. The rainiest months in Serra Negra are January, December, November and February, with each month seeing an average of 218 mm of rainfall.