September is a getaway to the beautiful autumn season of Wyoming with moderate temperatures and a brief splash of colors in the landscape that is usually brown prairie or white snowy. Early fall sees the average warm high temperatures of 60°F (15.6°C) to 80°F (26.7°C) range and the average low temperatures in the mild 32°F (0°C) to 47°F (8.3°C) range. Rain is slight to the tune of 1" (25mm) in many places with numerous sunny days as the skies are clear with little moisture in the air. Hordes of tourists flock Yellowstone during this time as the temperatures are in a pleasant 35°F (1.7°C) to 70°F (21.1°C) range, all the trails are open, and it is a great time to experience the wilderness in full bloom. Autumn is a great time to visit Wyoming as the weather is pleasant, and the days have comfortable temperatures, while the nights are ideal to light and sit by campfires - remember that the cold increases with altitude!