September in Grand Junction averages a daily high of 27.8°C with nights around 12.7°C. Expect roughly 6.5 wet days totalling 28.1mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Grand Junction is April–May.
Based on GRAND JUNCTION 6 ESE, CO US (7.7km), 1995–2024. 29 years of September data.