Gateway Arch National Park weather in August
August in Gateway Arch National Park: sweltering, rainy — a good time to visit.
#10 of 12 months in Gateway Arch National Park · #442 of 604 destinations to visit in August · comfort 67/100 (tier C)
Updated June 2026 · climate normals from ERA5 reanalysis
Gateway Arch National Park climate normals — August
| Daytime high | 30°C / 86°F | 🔥 sweltering |
|---|---|---|
| Nighttime low | 21°C / 70°F | |
| Feels like (high) | 34°C / 93°F | |
| Rainfall | 136 mm / 5.3 in | 🌧 rainy |
| Rainy days | 11 days | |
| Humidity | 73% | 💧 humid |
| Dew point | 20°C / 68°F | |
| Sunshine | 10.9 h/day | |
| Daylight | 13.6 h | |
| Wind | 13 km/h / 8 mph | |
| Air quality (US AQI) | 64 | 🙂 moderate |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Where is Gateway Arch National Park?
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Gateway Arch National Park in August — FAQ
- Is August a good time to visit Gateway Arch National Park?
- August in Gateway Arch National Park: sweltering, rainy — a good time to visit. It ranks #10 of 12 months for Gateway Arch National Park on SeasonMap's comfort score (67/100).
- What is the weather like in Gateway Arch National Park in August?
- In August, Gateway Arch National Park averages a daily high of 30.1°C and a low of 21.2°C, with about 135.8 mm of rain over roughly 11.2 rainy days.
- What is the air quality in Gateway Arch National Park in August?
- Gateway Arch National Park has a mean US Air Quality Index of about 64 in August.