Aspen, Colorado weather in September
Temperature, rain and sunshine in September: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in September
Excellent
Best time to visit: June – September
Best for skiing: December – April
What is the weather like in Aspen, Colorado in September?
In September, Aspen, Colorado is mild: daytime highs average 20 °C, and nights cool down to about 5 °C. The sun shines for around 8 hours a day. Rain falls on about 7 days, adding up to 35 mm. All in all, September is an excellent month for a holiday in Aspen, Colorado.
September compared
How the weather changes from August to October. Tap a month to open it.
| AugustAug | SeptemberSep | OctoberOct | |
|---|---|---|---|
| Score | 94 | 91 | 61 |
| Day | 24° | 20° | 12° |
| Night | 8° | 5° | −2° |
| Sun | 9 h | 8 h | 7 h |
| Rain days | 6 | 7 | 9 |
More details for September
- Daylight
- 12 h 30 min06:47 – 19:18
- UV index
- 8 · very highclear sky, noon (estimate)All months
- Muggy days
- 0 daysdew point 18 °C or moreAll months
- Wind
- 11 km/haverage daily peakAll months
- Cloud cover
- 32 %on averageAll months
- Hot days
- 0 days30 °C or more
- Snow days
- 1 day1 cm or more of fresh snowAll months
- Time zone
- UTC−6America/Denver
How the score comes together
- Temperatureweight 50 %100 %
- Sunshineweight 20 %82 %
- Few rainy daysweight 30 %81 %
Each factor is rated from 0 to 100 % and weighted for the travel style “Mountain air”.
What to pack in September
- Sunscreen
- Sunglasses & sun hat
- A jumper for the evenings
Aspen, Colorado in September: quick answers
Is Aspen, Colorado hot in September?
No. In September, Aspen, Colorado is mild: daytime highs average 20 °C and nights drop to about 5 °C.
Does it rain much in Aspen, Colorado in September?
Rain falls on about 7 days, adding up to 35 mm.
Aspen, Colorado month by month
The whole year in Aspen, ColoradoAll destinations: USAWhere to go in September
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences