Isle Royale National Park weather in August
August in Isle Royale National Park: nice, a little rain, with clean air — one of the best months to visit.
#2 of 12 months in Isle Royale National Park · #190 of 604 destinations to visit in August · comfort 85/100 (tier A)
Updated June 2026 · climate normals from ERA5 reanalysis
Isle Royale National Park climate normals — August
| Daytime high | 17°C / 63°F | 😎 nice |
|---|---|---|
| Nighttime low | 15°C / 59°F | |
| Feels like (high) | 16°C / 61°F | |
| Rainfall | 70 mm / 2.8 in | 🌦 some rain |
| Rainy days | 9 days | |
| Humidity | 88% | 💦 very humid |
| Dew point | 12°C / 54°F | |
| Sunshine | 11.2 h/day | |
| Daylight | 14.2 h | |
| Wind | 28 km/h / 17 mph | |
| Air quality (US AQI) | 40 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Where is Isle Royale National Park?
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Isle Royale National Park in August — FAQ
- Is August a good time to visit Isle Royale National Park?
- August in Isle Royale National Park: nice, a little rain, with clean air — one of the best months to visit. It ranks #2 of 12 months for Isle Royale National Park on SeasonMap's comfort score (85/100).
- What is the weather like in Isle Royale National Park in August?
- In August, Isle Royale National Park averages a daily high of 17.2°C and a low of 14.8°C, with about 70.3 mm of rain over roughly 8.8 rainy days.
- What is the air quality in Isle Royale National Park in August?
- Isle Royale National Park has a mean US Air Quality Index of about 40 in August.