Seattle weather in August
August in Seattle: warm, dry, with clean air — one of the best months to visit.
#2 of 12 months in Seattle · #45 of 604 destinations to visit in August · comfort 92/100 (tier S)
Updated June 2026 · climate normals from ERA5 reanalysis
Seattle climate normals — August
| Daytime high | 26°C / 79°F | 🌤 warm |
|---|---|---|
| Nighttime low | 15°C / 59°F | |
| Feels like (high) | 26°C / 79°F | |
| Rainfall | 17 mm / 0.7 in | ☀️ dry |
| Rainy days | 5 days | |
| Humidity | 67% | 💧 humid |
| Dew point | 14°C / 56°F | |
| Sunshine | 11.5 h/day | |
| Daylight | 14.2 h | |
| Wind | 12 km/h / 8 mph | |
| Air quality (US AQI) | 44 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Where is Seattle?
Loading map…
Seattle in August — FAQ
- Is August a good time to visit Seattle?
- August in Seattle: warm, dry, with clean air — one of the best months to visit. It ranks #2 of 12 months for Seattle on SeasonMap's comfort score (92/100).
- What is the weather like in Seattle in August?
- In August, Seattle averages a daily high of 26.2°C and a low of 15.1°C, with about 16.8 mm of rain over roughly 5 rainy days.
- What is the air quality in Seattle in August?
- Seattle has a mean US Air Quality Index of about 44 in August.