Rocky Mountain National Park in September
In September, Rocky Mountain National Park averages a high of 68°F and a low of 32°F, with 1.6 inches of precipitation (rain plus melted snow). About 596,000 people visit, the 4th busiest of 12 (busy). Days are 12 hours 25 minutes long.
- Quiet
- Moderate
- Busy
- Very busy
- Few or no visits (may be closed)
- Best months
- High / low
- 68° / 32°F
- Precipitation
- 1.6in
- Snow
- 0.4in
- Daylight
- 12h 25m
- Visitors
- 596,000
- Crowds
- Busy
Best months for weather and crowds instead: June (very busy).
Higher or lower in the park, expect a different picture: Waterdale, CO at 5,230 ft averages a September high of 76°F and a low of 45°F.
Weather 1991–2020 averages at Grand Lake 1 NW, CO, 9.2 miles from the park's center, 8,720 ft. Second station lower down: Waterdale, CO, 5,230 ft, 26.4 miles. Visitors National Park Service recreation visits, average of 2023–2025. Updated .
Other parks in September
| Park | High / low °F | Crowds | Weather |
|---|---|---|---|
| Black Canyon of the Gunnison National Park | 72° / 44° | Very busy | Mild, wet |
| Great Sand Dunes National Park | 72° / 44° | Moderate | Mild, wet |
| Arches National Park | 87° / 58° | Very busy | Hot |
| Wind Cave National Park | 76° / 46° | Busy | Mild |
| Mesa Verde National Park | 76° / 50° | Busy | Mild, wet |
Closures, reservations and alerts: Rocky Mountain National Park on nps.gov
All twelve months at Rocky Mountain · National parks to visit in September