Taking into account the local weather in Sao Jeronimo da Serra is an important factor for planning your visit, especially if you plan to spend your trip poolside. The hottest months are usually December and November with an average temp of 73°F, while the coldest months are July and June with an average of 64°F. The rainiest months in Sao Jeronimo da Serra are January, February, December, and October, with each month seeing an average of 9 inches of rainfall.