Aspen weather in September: Aspen, Colorado: normal highs, lows, rain and records for September
Aspen in September has a normal high of 72°F and a normal low of 40°F, a daily mean of 56°F, falling from 77°F on the 1st to 67°F by the 30th. Measurable precipitation falls on 9 days in a normal September, 1.43 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 22°C and low of 4°C, 36 mm of precipitation in September.
- NOAA stationAspen Pitkin County Airport
- Station IDUSW00093073
- Location39.22°N 106.87°W
- Elevation7,720 ft (2,353 m)
- Population6,556
- Jan 35° 9°
- Feb 38° 12°
- Mar 46° 21°
- Apr 55° 28°
- May 65° 35°
- Jun 77° 42°
- Jul 82° 48°
- Aug 80° 47°
- Sep 72° 40°
- Oct 60° 29°
- Nov 45° 19°
- Dec 34° 9°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Aspen in September?
The normal high is 72°F and the normal low 40°F, for a daily mean of 56.1°F. September is 7.2°F cooler than August and 11.7°F warmer than October. September is the 4th warmest month of the year in Aspen and the 5th wettest. Across the month the normal high falls 10°F, from 77°F on September 1 to 67°F on September 30. From one year to the next September's mean temperature typically moves about 1.9°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 54°F and 58°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 34%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 77°F | 44°F | 34% | 15% |
| September 8 | 75°F | 43°F | 33% | 15% |
| September 15 | 73°F | 40°F | 31% | 15% |
| September 22 | 70°F | 38°F | 29% | 15% |
| September 30 | 67°F | 35°F | 28% | 14% |
Every day of September: normal high, low and chance of precipitation (warmest afternoon September 1, coldest night September 30)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| September 1 | 77°F | 44°F | 34% | 15% | 13 h 10 min |
| September 2 | 77°F | 44°F | 33% | 15% | 13 h |
| September 3 | 76°F | 44°F | 33% | 15% | 13 h |
| September 4 | 76°F | 44°F | 33% | 15% | 13 h |
| September 5 | 76°F | 43°F | 33% | 15% | 13 h |
| September 6 | 76°F | 43°F | 33% | 15% | 12 h 50 min |
| September 7 | 75°F | 43°F | 33% | 15% | 12 h 50 min |
| September 8 | 75°F | 43°F | 33% | 15% | 12 h 50 min |
| September 9 | 75°F | 42°F | 33% | 16% | 12 h 50 min |
| September 10 | 74°F | 42°F | 32% | 16% | 12 h 40 min |
| September 11 | 74°F | 42°F | 32% | 16% | 12 h 40 min |
| September 12 | 74°F | 41°F | 32% | 16% | 12 h 40 min |
| September 13 | 74°F | 41°F | 32% | 15% | 12 h 40 min |
| September 14 | 73°F | 41°F | 32% | 15% | 12 h 30 min |
| September 15 | 73°F | 40°F | 31% | 15% | 12 h 30 min |
| September 16 | 72°F | 40°F | 31% | 15% | 12 h 30 min |
| September 17 | 72°F | 40°F | 31% | 15% | 12 h 30 min |
| September 18 | 72°F | 39°F | 30% | 15% | 12 h 20 min |
| September 19 | 71°F | 39°F | 30% | 15% | 12 h 20 min |
| September 20 | 71°F | 39°F | 30% | 15% | 12 h 20 min |
| September 21 | 71°F | 38°F | 30% | 15% | 12 h 20 min |
| September 22 | 70°F | 38°F | 29% | 15% | 12 h 10 min |
| September 23 | 70°F | 37°F | 29% | 15% | 12 h 10 min |
| September 24 | 69°F | 37°F | 29% | 15% | 12 h 10 min |
| September 25 | 69°F | 37°F | 28% | 15% | 12 h 10 min |
| September 26 | 69°F | 36°F | 28% | 15% | 12 h |
| September 27 | 68°F | 36°F | 28% | 15% | 12 h |
| September 28 | 68°F | 35°F | 28% | 15% | 12 h |
| September 29 | 67°F | 35°F | 28% | 15% | 11 h 50 min |
| September 30 | 67°F | 35°F | 28% | 14% | 11 h 50 min |
- Normal high
- 72°FSeptember average
- Normal low
- 40°FSeptember average
- Precipitation
- 1.43 inmonth total
- Days with precipitation
- 90.01 inch or more
- Nights at 32°F or colder
- 4
- Daylight
- 13 h 10 min to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 20
- Days at 80°F or more
- 3
- Sunshine
- 80%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00093073; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Aspen in September?
On a given September day the chance of 0.01 inch or more is 31% on average, highest around September 1 (34%). In all, 1.43 in falls on 9 days of a normal September.
In a normal September in Aspen, 4 nights fall to freezing.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00093073.
What are the records for September in Aspen?
The warmest September temperature on this station's record (since 1998) is 89°F, on September 3, 2019; the coldest is 17°F, on September 29, 1999. The wettest September brought 2.84 in (2002).
The September mean against the 1991-2020 normal of 56.1°F: 2021 58.6°F (+2.5), 2022 58.9°F (+2.8), 2023 56.2°F (+0.1), 2024 57.1°F (+1.0), 2025 55.4°F (−0.7), 2026 59.2°F (+3.1). 5 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 58.6°F | +2.5°F | 1.57 in |
| 2022 | 58.9°F | +2.8°F | 1.30 in |
| 2023 | 56.2°F | +0.1°F | 0.36 in |
| 2024 | 57.1°F | +1.0°F | 1.13 in |
| 2025 | 55.4°F | −0.7°F | 1.38 in |
| 2026 | 59.2°F | +3.1°F | 1.15 in |
Source: records: ACIS, station USW00093073; recent months: ACIS, station USW00093073. Records and recent months use complete months only.
How does September in Aspen compare across Colorado?
Across the 125 places PlainClimate covers in Colorado, September normal highs run from 62°F in Leadville to 86°F in Lamar; Aspen's is 72°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.