September is an excellent month at Gateway Arch — it ranks 6th of the twelve here. Expect about 71% fewer visitors than July, the park's peak — 139,931 visits on average. Days run around 80°F by afternoon and 59°F at night, with 12.4 hours of daylight.
September against the park's best
| Month | Verdict | Avg. visits | vs. peak | High | Low | Snow | Daylight |
|---|---|---|---|---|---|---|---|
| September (this page) | Excellent | 139,931 | −71% | 80°F | 59°F | 0" | 12.4 h |
| October (best) | Excellent | 125,733 | −74% | 70°F | 46°F | 0" | 11.1 h |
| July (peak crowds) | Tough | 476,195 | peak | 89°F | 69°F | 0" | 14.6 h |
Weather figures are for downtown St. Louis — the Cahokia station. Visits are 2021–2025 averages; climate normals cover 1991–2020. Conditions vary across the park; check current status before you go.
Common questions
Is September a good time to visit Gateway Arch?
Yes — it is one of the best months of the year here. September ranks 6 of 12 at Gateway Arch on crowds, weather, daylight, and access together.
How crowded is Gateway Arch in September?
About 139,931 recreation visits on average — 71% below July, the park's peak.
How warm is Gateway Arch in September?
Average highs around 80°F and lows around 59°F at the Cahokia station.
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