Denver weather in September
“Reliably warm, dry, and generous with light.”
Roughly 4 rainy days across the month, on average.
September in Denver brings pleasant early fall conditions with warm, sunny days and cool nights. Daytime temperatures average 28.3°C (82°F), while nights drop to a crisp 11.2°C (52°F). Rainfall is minimal at just 21.1mm across roughly 4 rainy days, and you'll enjoy an impressive 11 hours of sunshine daily. The thin mountain air means the sun feels stronger than the temperature suggests, but evenings require a light layer.
This is peak outdoor season in Denver. The summer crowds have thinned, making it ideal for hiking, visiting breweries, and exploring neighborhoods like RiNo and South Pearl Street. The Colorado Music Festival wraps up, and the city settles into a relaxed rhythm before October's cooler weather arrives. Locals love September for its perfect hiking conditions and low humidity.
For travelers planning a 2026 visit, September is one of the best months—you'll skip summer tourism peaks while enjoying stable weather. Pack layers to handle the 17°C (30°F) temperature swing between day and night, and bring sunscreen despite the cool mornings. Book accommodations early, as prices remain reasonable but availability tightens quickly.
What to pack for Denver in September
Layer strategically for Denver's dramatic temperature shifts. Mornings and evenings demand a light sweater or fleece, while afternoons are shirt-sleeve comfortable. Bring a light rain jacket just in case, sturdy walking shoes for mountain trails, and always pack sunscreen and sunglasses—Denver's high altitude intensifies UV exposure.
- Merino wool base layers
- Lightweight fleece jacket
- Water-resistant windbreaker
- Comfortable hiking boots
- Wide-brimmed sun hat
What to pack for Denver in September
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Where to stay in Denver
We don't review individual hotels — plenty of people do that well. What we do is send you to compare rooms in Denver across trusted platforms.
Compare hotels on Booking.com→Things worth doing
Hiking Rocky Mountain trails, exploring craft breweries on South Pearl Street, visiting Red Rocks Park and amphitheater, cycling Cherry Creek Bike Path.
September vs. the rest of the year
How this month compares in Denver. Tap any month to read more.
highlighted months are among the best time to visit.
Best time to visit Denver
September is one of the best months to visit Denver — alongside April, June, October. Ten-year climate data confirms it: comfortable temperatures, manageable rainfall, and a healthy dose of sunshine.
See the full best-time-to-visit guide for DenverOther places with a similar climate right now
Denver in September — FAQ
Q01Is September a good time to visit Denver?
Is September a good time to visit Denver?
Yes — this is one of the best months of the year to visit. In September, Denver averages a high of 28°C (83°F) and a low of 11°C (52°F), with 21mm of rainfall across roughly 4 rainy days.
Q02What is the average temperature in Denver in September?
What is the average temperature in Denver in September?
The average high temperature in Denver during September is 28°C (83°F), with an average low of 11°C (52°F). These figures are averaged from ten years of daily records (2015–2024, Open-Meteo Archive).
Q03How many rainy days does Denver have in September?
How many rainy days does Denver have in September?
Denver averages approximately 4 rainy days in September, with a total monthly rainfall of about 21mm. This is based on daily precipitation records where days with 1mm or more of rain are counted as rainy days.
Q04What should I pack for Denver in September?
What should I pack for Denver in September?
For Denver in September, pack light, breathable clothing (cotton or linen), sunscreen and sunglasses, comfortable walking shoes. These recommendations are based on the ten-year weather averages for this specific month.
Q05How crowded is Denver in September?
How crowded is Denver in September?
Tourist crowds in Denver during September are typically moderate — shoulder season, a sweet spot between crowds and weather. Consider this when planning accommodation — prices track crowd levels closely.