Early autumn · Weather & things to do
Denver in September
Denver cools off: highs slip to 82°F (28°C), from 89°F in August, with lows of 53°F (12°C) and about 1.4 in (36 mm) of rain.
September opens the best stretch on our comfort score, at 95/100 (the top score of the year).
- Avg high
- 82°F (28°C)
- Avg low
- 53°F (12°C)
- Rain
- 1.4 in (36 mm)
- Humidity
- 44%
- Cloud cover
- 38%
- Daylight
- ~12 h 15 min
- Comfort score
- 95/100 · Great
What September feels like
Warm afternoons near 82°F (28°C) make long days outdoors easy.
There's a big swing between day and night, about 16°C (29°F), so mornings and evenings feel much cooler than the afternoon.
Rain is moderate at about 1.4 in (36 mm) for the month.
Plan around September
September is one of Denver's best months on the climate data.
- Last warm month for a while: October highs fall to 67°F.
- Opens the best-scoring stretch on our comfort score: April & May and September & October.
- Comfort improves from 75/100 in August to 95/100.
- September sits inside the Jun – Sep window our Colorado Rockies route recommends.
What to pack for September
- Light, breathable clothes82°F afternoons
- Sunscreen, sunglasses and a hatstrong sun this month
- A warm layer for eveningsnights drop to 53°F
- Comfortable walking shoesmost picks involve some walking
What to do in Denver in September
September is good outdoor weather here, so these picks lean toward the open air.
Death & Co Denver
Serious cocktail bar inside the Ramble Hotel lobby, a short walk from RiNo's mural streets.
Why now September scores 95/100 for comfort, good conditions for being outside.
Denver Botanic Gardens
24 acres of themed gardens including a Japanese garden and a high-plains alpine collection.
Why now Our curated notes say it's best May–Sep.
Denver Union Station
Restored 1914 rail hall with bars, shops and a lounge-like Great Hall at the heart of LoDo.
Denver Central Market
Food hall in a restored RiNo warehouse with pizza, tacos, pastries and a central bar.
Larimer Square
Denver's oldest block, lined with Victorian buildings, string lights, shops and restaurants.
Why now Highs near 82°F and 1.4 in of monthly rain make this an easy outdoor pick.
Nearby in September
- Rocky Mountain NP in September~56 mi · highs 63°F, 1.7 in rain · 10°C (18°F) cooler by day, about as wet
- Breckenridge in September~59 mi · highs 62°F, 1.7 in rain · 11°C (19°F) cooler by day, about as wet
- Vail in September~73 mi · highs 67°F, 1.7 in rain · 8°C (14°F) cooler by day, about as wet
- Aspen in September~105 mi · highs 69°F, 1.8 in rain · 7°C (13°F) cooler by day, about as wet
These averages also cover City Park and Downtown Denver & 16th Street.
NASA POWER 2001–2025 monthly averages on a ~50 km grid, temperatures adjusted from the grid cell's ~2,095 m to Denver's ~1,597 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.
Denver in September: quick answers
Is September a good time to visit Denver?
Yes. On the climate data it's one of the best months, scoring 95/100. Expect highs of 82°F (28°C) and 1.4 in (36 mm) of rain. September is inside the Jun – Sep window our Colorado Rockies route recommends.
How hot is Denver in September?
Average highs are 82°F (28°C) and average lows 53°F (12°C), making it the 4th-warmest month by daytime highs.
Does it rain a lot in Denver in September?
Not much: about 1.4 in (36 mm) of rain falls across September on average, the 6th-wettest month of the year. The annual total is about 17.3 in (440 mm).
What should I pack for Denver in September?
Bring light, breathable clothes (82°F afternoons), sunscreen, sunglasses and a hat (strong sun this month), a warm layer for evenings (nights drop to 53°F) and comfortable walking shoes (most picks involve some walking).
Routes in season in September
- Colorado Rockies Jun – Sep
Planning Denver in September?
Plan it together in TripsCircle: one itinerary, one shared packing list and costs split as you go.