Mount Rainier National Park weather in August
August in Mount Rainier National Park: cool, dry, with clean air — one of the best months to visit.
#1 of 12 months in Mount Rainier National Park · #27 of 604 destinations to visit in August · comfort 93/100 (tier S)
Updated June 2026 · climate normals from ERA5 reanalysis
Mount Rainier National Park climate normals — August
| Daytime high | 16°C / 60°F | 🙂 cool |
|---|---|---|
| Nighttime low | 4°C / 38°F | |
| Feels like (high) | 13°C / 55°F | |
| Rainfall | 20 mm / 0.8 in | ☀️ dry |
| Rainy days | 6 days | |
| Humidity | 63% | 💧 humid |
| Dew point | 2°C / 36°F | |
| Sunshine | 11.8 h/day | |
| Daylight | 14.2 h | |
| Wind | 11 km/h / 7 mph | |
| Air quality (US AQI) | 39 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Where is Mount Rainier National Park?
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Mount Rainier National Park in August — FAQ
- Is August a good time to visit Mount Rainier National Park?
- August in Mount Rainier National Park: cool, dry, with clean air — one of the best months to visit. It ranks #1 of 12 months for Mount Rainier National Park on SeasonMap's comfort score (93/100).
- What is the weather like in Mount Rainier National Park in August?
- In August, Mount Rainier National Park averages a daily high of 15.5°C and a low of 3.5°C, with about 19.5 mm of rain over roughly 5.6 rainy days.
- What is the air quality in Mount Rainier National Park in August?
- Mount Rainier National Park has a mean US Air Quality Index of about 39 in August.