Best time to visit Isle Royale National Park
The short answer
Best months to visit Isle Royale National Park: July–September. Daily highs run about 60–65°F, with about 80% of July's visitors.
Hardest months: January–April, mostly because of cold weather.
How we picked these months: each month is scored on daily highs (65–82°F is ideal), rain, snow and seasonal closures, then reduced by up to 30% for crowds, measured against the park's busiest month. We list the months within 15% of the top score (at most 5).
Weather and crowds by month
Isle Royale National Park month by month
Park-wide averages across 3 locations. Crowds compare each month with the park's busiest month: Quiet is under 35% of it, Moderate under 60%, Busy under 85%, Peak above that.
| Month | Rating | High / low | Rain | Snow | Crowds | Closures |
|---|---|---|---|---|---|---|
| January | Poor | 22° / 13°F | 0.1 in | 11.2 in | Quiet | Annual Winter Closure (November 1 to April 15) |
| February | Poor | 20° / 10°F | 0.2 in | 12.4 in | Quiet | Annual Winter Closure (November 1 to April 15) |
| March | Poor | 30° / 21°F | 0.4 in | 8.5 in | Quiet | Annual Winter Closure (November 1 to April 15) |
| April | Poor | 38° / 30°F | 1.6 in | 11.0 in | Quiet | Annual Winter Closure (November 1 to April 15) |
| May | Fair | 49° / 39°F | 2.6 in | 1.2 in | Quiet | – |
| June | Good | 58° / 46°F | 2.7 in | – | Busy | – |
| July | Best | 65° / 54°F | 2.5 in | – | Peak | – |
| August | Best | 66° / 58°F | 2.4 in | – | Peak | – |
| September | Best | 61° / 55°F | 3.4 in | – | Moderate | – |
| October | Fair | 50° / 44°F | 3.0 in | 1.2 in | Quiet | – |
| November | Poor | 38° / 31°F | 1.5 in | 8.0 in | Quiet | Annual Winter Closure (November 1 to April 15) |
| December | Poor | 30° / 21°F | 0.6 in | 13.9 in | Quiet | Annual Winter Closure (November 1 to April 15) |
Weather by location
Parks with a big range of elevation can differ a lot from one area to another. Open a location to see its own numbers.
Park-wide (center of the park)
| Month | High | Low | Rain | Snow |
|---|---|---|---|---|
| January | 22°F | 12°F | 0.1 in | 11.7 in |
| February | 19°F | 9°F | 0.2 in | 12.5 in |
| March | 29°F | 20°F | 0.4 in | 8.8 in |
| April | 38°F | 29°F | 1.6 in | 11.4 in |
| May | 50°F | 38°F | 2.5 in | 1.2 in |
| June | 58°F | 46°F | 2.6 in | – |
| July | 65°F | 54°F | 2.5 in | – |
| August | 66°F | 58°F | 2.4 in | – |
| September | 61°F | 54°F | 3.3 in | – |
| October | 49°F | 43°F | 3.0 in | 1.4 in |
| November | 37°F | 30°F | 1.5 in | 8.1 in |
| December | 29°F | 21°F | 0.7 in | 14.1 in |
Rock Harbor
| Month | High | Low | Rain | Snow |
|---|---|---|---|---|
| January | 22°F | 13°F | 0.1 in | 11.9 in |
| February | 20°F | 10°F | 0.2 in | 12.8 in |
| March | 30°F | 21°F | 0.4 in | 7.9 in |
| April | 38°F | 30°F | 1.6 in | 9.7 in |
| May | 49°F | 38°F | 2.5 in | 1.0 in |
| June | 57°F | 45°F | 2.6 in | – |
| July | 65°F | 54°F | 2.5 in | – |
| August | 66°F | 59°F | 2.5 in | – |
| September | 62°F | 55°F | 3.4 in | – |
| October | 50°F | 44°F | 3.0 in | 1.3 in |
| November | 38°F | 31°F | 1.6 in | 8.2 in |
| December | 30°F | 22°F | 0.7 in | 14.2 in |
Windigo
| Month | High | Low | Rain | Snow |
|---|---|---|---|---|
| January | 23°F | 13°F | 0.1 in | 10.0 in |
| February | 21°F | 10°F | 0.2 in | 11.8 in |
| March | 31°F | 21°F | 0.3 in | 8.9 in |
| April | 39°F | 30°F | 1.7 in | 11.8 in |
| May | 50°F | 39°F | 2.7 in | 1.3 in |
| June | 58°F | 47°F | 2.8 in | – |
| July | 64°F | 54°F | 2.6 in | – |
| August | 66°F | 59°F | 2.3 in | – |
| September | 62°F | 55°F | 3.5 in | – |
| October | 50°F | 44°F | 2.9 in | 1.0 in |
| November | 38°F | 31°F | 1.3 in | 7.8 in |
| December | 30°F | 21°F | 0.5 in | 13.3 in |
Isle Royale National Park by season
Spring (March–May)
Spring (March–May) is a difficult time to visit Isle Royale National Park. Daily highs average 30–49°F and lows 21–39°F. Expect about 1.5 in of rain a month and 6.9 in of snow, with up to 6 in on the ground. Visitor numbers run 0–16% of the busiest month, which is quiet by this park's standards. Closures listed by the NPS: Annual Winter Closure (November 1 to April 15).
Summer (June–August)
Summer (June–August) is among the best times to visit Isle Royale National Park. Daily highs average 58–66°F and lows 46–58°F. Expect about 2.5 in of rain a month and little or no snow. Visitor numbers run 67–100% of the busiest month, which is peak by this park's standards.
Fall (September–November)
Fall (September–November) is a mixed time to visit Isle Royale National Park. Daily highs average 38–61°F and lows 31–55°F. Expect about 2.6 in of rain a month and 3.1 in of snow, with up to 0 in on the ground. Visitor numbers run 0–38% of the busiest month, which is quiet by this park's standards. Closures listed by the NPS: Annual Winter Closure (November 1 to April 15).
Winter (December–February)
Winter (December–February) is a difficult time to visit Isle Royale National Park. Daily highs average 20–30°F and lows 10–21°F. Expect about 0.3 in of rain a month and 12.5 in of snow, with up to 6 in on the ground. Visitor numbers run 0% of the busiest month, which is quiet by this park's standards. Closures listed by the NPS: Annual Winter Closure (November 1 to April 15).
For what to do in each season, see our guides to trip planning, fees and hours, trails, camping and things to do, where the planning page also has our written advice on when to go. In-depth topic guides cover individual places and hikes.
Seasonal closures
Closures listed in the NPS operating hours, shown as month and day. Exact dates change every year with snow and staffing.
- Annual Winter Closure (November 1 to April 15): closed about Nov 1 – Apr 15 (whole park)
- Isle Royale National Park is open annually from April 16 to October 31.
- The island and its surrounding islands are closed to all visitors from November 1 to April 15 due to extreme winter weather conditions and for the safety and protection of visitors.
What the National Park Service says about the weather
Isle Royale National Park is a remote island wilderness in the middle of Lake Superior. Weather influences traveling to and from the island, as well as your trip once you arrive. For the most up-to-date weather information, call (906) 482-0984 or email isro_parkinfo@nps.gov prior to your trip.
Weather: modeled monthly averages for 2014-2023 (Open-Meteo Archive API), averaged over 3 locations. Modeled grid cells can read cooler than weather stations in deep canyons and deserts, and warmer or colder at high elevation. Visits: monthly recreation visits for 2021-2024, National Park Service.
