Isle Royale National Park in August
In August, Isle Royale National Park averages a high of 73°F and a low of 52°F, with 3.0 inches of precipitation (rain plus melted snow). About 8,900 people visit, the busiest month. Days are 14 hours 18 minutes long.
- Quiet
- Moderate
- Busy
- Very busy
- Few or no visits (may be closed)
- Best months
- High / low
- 73° / 52°F
- Precipitation
- 3.0in
- Snow
- 0in
- Daylight
- 14h 18m
- Visitors
- 8,900
- Crowds
- Very busy
Best months for weather and crowds instead: May (quiet), June (busy) and September (moderate).
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 August
| Park | High / low °F | Crowds | Weather |
|---|---|---|---|
| Voyageurs National Park | 76° / 49° | Very busy | Mild, wet |
| Sleeping Bear Dunes National Lakeshore | 75° / 59° | Very busy | Mild |
| Indiana Dunes National Park | 80° / 63° | Very busy | Mild, wet |
| Cuyahoga Valley National Park | 81° / 59° | Very busy | Hot |
| Gateway Arch National Park | 88° / 66° | Busy | Hot |
Closures, reservations and alerts: Isle Royale National Park on nps.gov
All twelve months at Isle Royale · National parks to visit in August