Isle Royale National Park weather in May
May in Isle Royale National Park: cold, a little rain, with clean air — a great time to visit.
#5 of 12 months in Isle Royale National Park · #409 of 604 destinations to visit in May · comfort 76/100 (tier B)
Updated June 2026 · climate normals from ERA5 reanalysis
Isle Royale National Park climate normals — May
| Daytime high | 5°C / 42°F | 🧥 cold |
|---|---|---|
| Nighttime low | 3°C / 37°F | |
| Feels like (high) | 2°C / 36°F | |
| Rainfall | 57 mm / 2.2 in | 🌦 some rain |
| Rainy days | 8 days | |
| Humidity | 85% | 💦 very humid |
| Dew point | 2°C / 35°F | |
| Sunshine | 11.3 h/day | |
| Daylight | 15.2 h | |
| Wind | 29 km/h / 18 mph | |
| Snowfall | 4.1 cm / 1.6 in | |
| Air quality (US AQI) | 37 | 🍃 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 May — FAQ
- Is May a good time to visit Isle Royale National Park?
- May in Isle Royale National Park: cold, a little rain, with clean air — a great time to visit. It ranks #5 of 12 months for Isle Royale National Park on SeasonMap's comfort score (76/100).
- What is the weather like in Isle Royale National Park in May?
- In May, Isle Royale National Park averages a daily high of 5.4°C and a low of 2.7°C, with about 56.8 mm of rain over roughly 7.8 rainy days.
- What is the air quality in Isle Royale National Park in May?
- Isle Royale National Park has a mean US Air Quality Index of about 37 in May.
- Does it snow in Isle Royale National Park in May?
- Isle Royale National Park sees roughly 4.1 cm of snowfall in May.