September in Arvada averages a daily high of 26.4°C with nights around 7.7°C. Expect roughly 6.8 wet days totalling 35.8mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Arvada is May–June.
Based on WHEAT RIDGE 2, CO US (3.9km), 1995–2024. 29 years of September data.