Gateway Arch National Park in September
In September, Gateway Arch National Park averages a high of 81°F and a low of 57°F, with 3.4 inches of precipitation (rain plus melted snow). About 171,000 people visit, the 7th busiest of 12 (moderate). Days are 12 hours 23 minutes long.
- Quiet
- Moderate
- Busy
- Very busy
- Few or no visits (may be closed)
- Best months
- High / low
- 81° / 57°F
- Precipitation
- 3.4in
- Snow
- –in
- Daylight
- 12h 23m
- Visitors
- 171,000
- Crowds
- Moderate
Best months for weather and crowds instead: March (moderate), October (quiet) and November (quiet).
Weather 1991–2020 averages at Cahokia St Louis AP, IL, 3.7 miles from the park's center, 413 ft. Visitors National Park Service recreation visits, average of 2023–2025. Updated .
Other parks in September
| Park | High / low °F | Crowds | Weather |
|---|---|---|---|
| Ozark National Scenic Riverways | 81° / 54° | Busy | Hot |
| Mammoth Cave National Park | 85° / 60° | Busy | Hot |
| Buffalo National River | 78° / 59° | Moderate | Mild |
| Indiana Dunes National Park | 74° / 56° | Moderate | Mild, wet |
| Hot Springs National Park | 86° / 64° | Moderate | Hot |
Closures, reservations and alerts: Gateway Arch National Park on nps.gov
All twelve months at Gateway Arch · National parks to visit in September