Planning for the weather is a good way to make your trip to Nova Petropolis relaxing and enjoyable, especially when you're splurging. The hottest months are usually January and February with an average temp of 69°F, while the coldest months are July and June with an average of 55°F. The rainiest months in Nova Petropolis are October, January, September, and December, with each month seeing an average of 8 inches of rainfall.