Denver weather in September
September in Denver: warm, dry, with clean air — one of the best months to visit.
#2 of 12 months in Denver · #40 of 604 destinations to visit in September · comfort 91/100 (tier S)
Updated June 2026 · climate normals from ERA5 reanalysis
Denver climate normals — September
| Daytime high | 28°C / 82°F | 🌤 warm |
|---|---|---|
| Nighttime low | 11°C / 52°F | |
| Feels like (high) | 25°C / 77°F | |
| Rainfall | 29 mm / 1.1 in | ☀️ dry |
| Rainy days | 5 days | |
| Humidity | 48% | 🍃 comfortable |
| Dew point | 5°C / 40°F | |
| Sunshine | 11 h/day | |
| Daylight | 12.4 h | |
| Wind | 15 km/h / 9 mph | |
| Snowfall | 3.5 cm / 1.4 in | |
| Air quality (US AQI) | 38 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
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Denver in September — FAQ
- Is September a good time to visit Denver?
- September in Denver: warm, dry, with clean air — one of the best months to visit. It ranks #2 of 12 months for Denver on SeasonMap's comfort score (91/100).
- What is the weather like in Denver in September?
- In September, Denver averages a daily high of 27.5°C and a low of 10.9°C, with about 28.6 mm of rain over roughly 5.2 rainy days.
- What is the air quality in Denver in September?
- Denver has a mean US Air Quality Index of about 38 in September.
- Does it snow in Denver in September?
- Denver sees roughly 3.5 cm of snowfall in September.