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In terms of precipitation, rainfall in McAllen ranges from 0.9 - 4.5 inches per month. September is typically the wettest month, when rainfall can reach 4.5 in. November is typically the driest time to visit McAllen when rainfall is around 0.9 in.
If weather is an important factor for your trip to McAllen, use this chart to help with planning. For those seeking warmer temperatures, August is the ideal time of year to visit, when temperatures reach an average of 87.8 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 60.8 F).