Other facts from our historical weather data: Does Petrolina have a dry season? Yes, the months of May, June, July, August, September and October are very dry. Which is the hottest month in Petrolina? October has an average maximum temperature of 36°C (97°F) and is the hottest month of the year. Which is the coolest month in Petrolina? The coolest month is August with an average maximum temperature of 31°C (88°F). Which is the wettest month in Petrolina? March tops the wettest month list with 90mm (3.5 in) of rainfall. Which is the driest month in Petrolina? September is the driest month with 3mm (0.1 in) of precipitation. Which is the sunniest month in Petrolina? August is the sunniest month with an average of 264 hours of sunshine. No idea where to travel to this year? We have a tool that recommends destinations based on your ideal conditions. Find out where to go with our weather planner.