In terms of precipitation, rainfall in Petrolina ranges from 0.1 - 4.0 inches per month. March is typically the wettest month, when rainfall can reach 4.0 in. July is typically the driest time to visit Petrolina when rainfall is around 0.1 in.
If weather is an important factor for your trip to Petrolina, use this chart to help with planning. For those seeking warmer temperatures, October is the ideal time of year to visit, when temperatures reach an average of 82.4 F. Travelers looking to avoid the cold should look outside of July, when temperatures are typically at their lowest (around 75.2 F).