This report describes the typical weather at the Grand Canyon National Park Airport (Grand Canyon National Park, Arizona, United States) weather station over the course of an average September. It is based on the historical records from 1981 to 2012. Earlier records are either unavailable or unreliable.he probability that precipitation will be observed at this location varies throughout the month. Precipitation is most likely around September 2, occurring in 30% of days. Precipitation is least likely around September 30, occurring in 19% of days.