Early autumn · Weather & things to do
Aspen in September
Aspen cools off: highs slip to 69°F (20°C), from 76°F in August, with lows of 42°F (6°C) and about 1.8 in (46 mm) of rain.
At 95/100 for comfort (2nd of 12), it's one of the best months to visit.
- Avg high
- 69°F (20°C)
- Avg low
- 42°F (6°C)
- Rain
- 1.8 in (46 mm)
- Humidity
- 56%
- Cloud cover
- 44%
- Daylight
- ~12 h 14 min
- Comfort score
- 95/100 · Great
What September feels like
Days are mild at around 69°F (20°C): comfortable for walking all day, with a layer for the evening.
There's a big swing between day and night, about 15°C (26°F), so mornings and evenings feel much cooler than the afternoon.
Rain is moderate at about 1.8 in (46 mm) for the month.
Plan around September
September is one of Aspen's best months on the climate data.
- Last of the best-scoring months: by October, the score drops to 75/100.
- Comfort improves from 91/100 in August to 95/100.
- September sits inside the Jun – Sep window our Colorado Rockies route recommends.
- Our Breckenridge, Vail & Aspen route recommends Dec – Mar, so September falls outside its suggested window.
What to pack for September
- A warm layer for eveningsnights drop to 42°F
- Comfortable walking shoesmost places below are best reached on foot or with short walks
What to do in Aspen in September
With conditions on your side, the picks below favor time outside.
Maroon Bells
Twin 14,000-foot peaks reflected in Maroon Lake; the Scenic Loop is easy.
Why now Our curated notes say it's best sunrise, late Sep for aspens.
Independence Pass
12,095-foot Continental Divide crossing with short tundra walks at the top.
Why now Our curated notes say it's best Jun–Sep.
Aspen Highlands
Ski area west of town known for Highland Bowl, a steep bowl reached by a hike along the ridge from the top lift.
Why now September scores 95/100 for comfort, good conditions for being outside.
Crater Lake Trail
3.6-mile round trip from Maroon Lake to a quieter lake right under the Bells.
Why now Highs near 69°F and 1.8 in of monthly rain make this an easy outdoor pick.
Cloud Nine Alpine Bistro
Mountain hut on Aspen Highlands serving fondue and raclette, known for its lively afternoon lunch seating.
Wheeler Opera House
Sandstone opera house built in 1889 by silver baron Jerome Wheeler, now hosting concerts, comedy and films.
Nearby in September
- Vail in September~39 mi · highs 67°F, 1.7 in rain · similar daytime temperatures, about as wet
- Breckenridge in September~46 mi · highs 62°F, 1.7 in rain · 4°C (6°F) cooler by day, about as wet
- Rocky Mountain NP in September~100 mi · highs 63°F, 1.7 in rain · 3°C (5°F) cooler by day, about as wet
- Denver in September~105 mi · highs 82°F, 1.4 in rain · 7°C (13°F) warmer by day, about as wet
NASA POWER 2001–2025 monthly averages on a ~50 km grid, temperatures adjusted from the grid cell's ~3,268 m to Aspen's ~2,405 m elevation (standard lapse rate). Comfort scores weigh temperature, rain, humidity and cloud: see how we score each month. Check a forecast before you go.
Aspen in September: quick answers
Is September a good time to visit Aspen?
Yes. On the climate data it's one of the best months, scoring 95/100. Expect highs of 69°F (20°C) and 1.8 in (46 mm) of rain. September is inside the Jun – Sep window our Colorado Rockies route recommends.
How hot is Aspen in September?
Average highs are 69°F (20°C) and average lows 42°F (6°C), making it the 4th-warmest month by daytime highs.
Does it rain a lot in Aspen in September?
Not much: about 1.8 in (46 mm) of rain falls across September on average, the 5th-wettest month of the year. The annual total is about 20.7 in (527 mm).
What should I pack for Aspen in September?
Bring a warm layer for evenings (nights drop to 42°F) and comfortable walking shoes (most places below are best reached on foot or with short walks).
Routes in season in September
- Colorado Rockies Jun – Sep
Planning Aspen in September?
Share this September plan with your group, poll everyone on dates and keep the packing list in one place.