Seattle weather in May
May in Seattle: nice, a little rain, with clean air — an excellent time to visit.
#5 of 12 months in Seattle · #246 of 604 destinations to visit in May · comfort 84/100 (tier A)
Updated June 2026 · climate normals from ERA5 reanalysis
Seattle climate normals — May
| Daytime high | 19°C / 65°F | 😎 nice |
|---|---|---|
| Nighttime low | 9°C / 48°F | |
| Feels like (high) | 18°C / 64°F | |
| Rainfall | 76 mm / 3 in | 🌦 some rain |
| Rainy days | 12 days | |
| Humidity | 76% | 💦 very humid |
| Dew point | 8°C / 47°F | |
| Sunshine | 10.7 h/day | |
| Daylight | 15.1 h | |
| Wind | 13 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.
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Seattle in May — FAQ
- Is May a good time to visit Seattle?
- May in Seattle: nice, a little rain, with clean air — an excellent time to visit. It ranks #5 of 12 months for Seattle on SeasonMap's comfort score (84/100).
- What is the weather like in Seattle in May?
- In May, Seattle averages a daily high of 18.5°C and a low of 8.8°C, with about 76 mm of rain over roughly 12 rainy days.
- What is the air quality in Seattle in May?
- Seattle has a mean US Air Quality Index of about 44 in May.