Isle Royale National Park in May
In May, Isle Royale National Park averages a high of 58°F and a low of 37°F, with 3.1 inches of precipitation (rain plus melted snow). About 1,500 people visit, the 5th busiest of 12 (quiet). Days are 15 hours 09 minutes long.
- Quiet
- Moderate
- Busy
- Very busy
- Few or no visits (may be closed)
- Best months
- High / low
- 58° / 37°F
- Precipitation
- 3.1in
- Snow
- 0.2in
- Daylight
- 15h 9m
- Visitors
- 1,500
- Crowds
- Quiet
May is one of the best months to visit: mild, wet weather with quiet crowds.
Weather 1991–2020 averages at Grand Portage, MN, 41.1 miles from the park's center, 730 ft. Visitors National Park Service recreation visits, average of 2023–2025. Updated .
Other parks in May
| Park | High / low °F | Crowds | Weather |
|---|---|---|---|
| Voyageurs National Park | 64° / 37° | Busy | Mild, wet |
| Sleeping Bear Dunes National Lakeshore | 62° / 43° | Quiet | Mild, wet |
| Indiana Dunes National Park | 68° / 50° | Busy | Mild, wet |
| Cuyahoga Valley National Park | 70° / 47° | Very busy | Mild, wet |
| Gateway Arch National Park | 77° / 57° | Moderate | Mild, wet |
Closures, reservations and alerts: Isle Royale National Park on nps.gov
All twelve months at Isle Royale · National parks to visit in May