Rocky Mountain · September
Rocky Mountain in September
September is a busy time to visit Rocky Mountain — quieter than August, busier than October.
Expect heavy crowds (8/10), highs near 69°F, about 12.4 hours of daylight, and 2 seasonal closures in effect.
Crowd score
How busy it gets
Approaching peak season — expect full lots by mid-morning and busy overlooks.
About 73% of this park's busiest month.
Source: NPS Visitor Use Statistics, 2023–2025
Data: NPS visitation 2023–2025 · crowd scores computed Oct 2026 · alerts checked Oct 18, 2026. How this is calculated →
Computed from federal data · Methodology by Sharon Ben-Moshe
Visitation
Typical September visits vs. the year
September draws about 12% of Rocky Mountain’s yearly visitors.
Typical monthly recreation visits, averaged over the most recent three full years.
Source: NPS Visitor Use Statistics, 2023–2025
Weather
September weather
- Avg high
- 69°F
- Avg low
- 39°F
- Precipitation
- 1.4"
- Sunrise
- 5:43 AM
- Sunset
- 6:10 PM
- Daylight
- 12.4h
Source: NOAA 1991–2020 climate normals, Estes Park
What's open
Rocky Mountain in September: access
Open 24 hours; Trail Ridge Road closed mid-Oct to late May
Seasonal closures may apply:
- Park Closure
Trail Ridge Road is Closed at Many Parks Curve & Milner Pass
Due to recent winter storms, Trail Ridge Road is temporarily closed on the east side of the park at Many Parks Curve and at Milner Pass on the west side of the park. Call the Trail Ridge Road recorded line at 970-586-1222 for the most up-to-date conditions.
Details on nps.gov → - Information
Trail Ridge Road closed for winter
Trail Ridge Road, the highest continuous paved road in the U.S., typically closes mid-October and reopens by Memorial Day.
Details on nps.gov →
Source: NPS Data API
Conditions
Current alerts
No additional active alerts or warnings reported for this park.
Source: NPS Data API
Context
Rocky Mountain crowds across the year
Alternatives
Quieter nearby in September
FAQ
Rocky Mountain in September
How busy is Rocky Mountain in September?
September rates 8/10 for crowds (Busy) at Rocky Mountain National Park — about 73% of its busiest month. Typical recreation visits: 495,709.
What is the weather like at Rocky Mountain in September?
In September, Rocky Mountain averages a high of 69°F and a low of 39°F, with about 1.4 inches of precipitation.
How much does it cost to visit Rocky Mountain?
Entrance to Rocky Mountain costs $30 ($30 per private vehicle, valid 1 day; timed-entry reservations in peak season).
When is Rocky Mountain least crowded?
Rocky Mountain is quietest in January and February. If your dates are flexible, those months bring the thinnest crowds of the year.
How many hours of daylight does Rocky Mountain get in September?
In mid-September, Rocky Mountain gets about 12.4 hours of daylight, with sunrise around 5:43 AM and sunset around 6:10 PM.