Gateway Arch National Park in August
Gateway Arch National Park · crowd + weather almanac
August crowd level
moderate
about 213,000 visits in a
typical August
The 2nd-busiest month of the year ·
median of 2016–2025 official NPS counts
August is the 2nd-busiest month of the year at Gateway Arch National Park: about 213,000 recreation visits in a typical August (12% of the year's traffic, and 45% of what the peak month, July, sees). Crowds are middling — noticeably lighter than peak season. Weather-wise, August days at the Cahokia, IL station typically top out around 87°F with nights near 67°F, and about 3.1 inches of precipitation falls over the month.
- Typical August: 213,218 recreation visits (median 2016–2025); the range across those years ran 31,610 (2020) to 322,088 (2024).
- Busier than 10 of the other 11 months.
- 1991–2020 August normals at Cahokia, IL: high 87°F, low 67°F, 3.09 in precipitation, 0.0 in snow.
- Similar daytime temperatures, thinner crowds: September typically runs 80°F days with about 42% fewer visits (124,000 vs 213,000).
August weather (1991–2020 normals)
| Typical daytime high | 87°F |
|---|---|
| Typical overnight low | 67°F |
| Precipitation (monthly normal) | 3.09 in |
| Snowfall (monthly normal) | 0.0 in |
| Measured at | Cahokia, IL (USC00111160), 4.0 mi from the park reference point, elev. 400 ft |
Every month at Gateway Arch
| Month | Typical visits | Crowds | High / Low | Precip |
|---|---|---|---|---|
| January | 39,056 | quietest stretch | 41°F / 22°F | 2.7 in |
| February | 51,742 | quietest stretch | 46°F / 26°F | 2.3 in |
| March | 121,804 | quiet | 56°F / 35°F | 3.5 in |
| April | 109,703 | quiet | 68°F / 45°F | 4.6 in |
| May | 140,929 | quiet | 76°F / 56°F | 4.8 in |
| June | 209,875 | moderate | 85°F / 65°F | 4.3 in |
| July | 470,489 | busiest stretch | 88°F / 69°F | 5.0 in |
| August | 213,218 | moderate | 87°F / 67°F | 3.1 in |
| September | 124,285 | quiet | 80°F / 59°F | 3.4 in |
| October | 117,702 | quiet | 70°F / 46°F | 3.0 in |
| November | 89,065 | quiet | 56°F / 35°F | 3.3 in |
| December | 70,685 | quiet | 45°F / 27°F | 2.8 in |