Best time to visit Isle Royale National Park
May, June and September have the mildest temperatures at Isle Royale, though they are among the wetter months. August is busiest, with about 8,900 visitors. May is the quietest. January, February, March, April, October, November and December see few or no visitors, so parts of the park may be closed: check nps.gov.
- Quiet
- Moderate
- Busy
- Very busy
- Few or no visits (may be closed)
- Best months
Month by month
- Station
- Grand Portage, MN USC00213296
- Lat / lon
- 47.97, -89.69
- Elevation
- 730 ft
- From park center
- 41.1 mi
- Normals
- 1991–2020
- Visits
- 2023–2025
| Field | Jan | Feb | Mar | Apr | Maybest | Junbest | Jul | Aug | Sepbest | Oct | Nov | Dec | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| High, °F | 20° | 24° | 34° | 45° | 58° | 68° | 74° | 73° | 65° | 51° | 38° | 26° | 48° |
| Low, °F | 1° | 2° | 13° | 26° | 37° | 46° | 52° | 52° | 44° | 33° | 22° | 9° | 28° |
| Precipitation, in | 1.4 | 1.0 | 1.3 | 2.8 | 3.1 | 3.6 | 3.4 | 3.0 | 3.1 | 3.4 | 2.6 | 1.7 | 30.6 |
| Snow, in | 12.2 | 8.0 | 8.0 | 7.7 | 0.2 | 0 | 0 | 0 | 0 | 0.5 | 6.7 | 11.9 | 55.2 |
| Daylight, h:mm | 8:46 | 10:08 | 11:44 | 13:34 | 15:09 | 16:01 | 15:40 | 14:18 | 12:31 | 10:44 | 9:10 | 8:23 | |
| Visitors, thousands | 0 | 0 | 0 | 0 | 2 | 6 | 9 | 9 | 3 | 0 | 0 | 0 | 29 |
| Crowds | Few or no visits | Few or no visits | Few or no visits | Few or no visits | Quiet | Busy | Very busy | Very busy | Moderate | Few or no visits | Few or no visits | Few or no visits | |
| Weather | Cold | Cold | Cold | Cool | Mild, wet | Mild, wet | Mild, wet | Mild, wet | Mild, wet | Cool | Cold | Cold |
| Month | High °F | Low °F | Precip., in | Snow, in | Daylight | Visitors | Crowds | Weather |
|---|---|---|---|---|---|---|---|---|
| January | 20° | 1° | 1.4 | 12.2 | 8:46 | 0 | Few or no visits | Cold |
| February | 24° | 2° | 1.0 | 8.0 | 10:08 | 0 | Few or no visits | Cold |
| March | 34° | 13° | 1.3 | 8.0 | 11:44 | 0 | Few or no visits | Cold |
| April | 45° | 26° | 2.8 | 7.7 | 13:34 | 68 | Few or no visits | Cool |
| Maybest | 58° | 37° | 3.1 | 0.2 | 15:09 | 1,500 | Quiet | Mild, wet |
| Junebest | 68° | 46° | 3.6 | 0 | 16:01 | 6,100 | Busy | Mild, wet |
| July | 74° | 52° | 3.4 | 0 | 15:40 | 8,600 | Very busy | Mild, wet |
| August | 73° | 52° | 3.0 | 0 | 14:18 | 8,900 | Very busy | Mild, wet |
| Septemberbest | 65° | 44° | 3.1 | 0 | 12:31 | 3,500 | Moderate | Mild, wet |
| October | 51° | 33° | 3.4 | 0.5 | 10:44 | 200 | Few or no visits | Cool |
| November | 38° | 22° | 2.6 | 6.7 | 9:10 | 0 | Few or no visits | Cold |
| December | 26° | 9° | 1.7 | 11.9 | 8:23 | 0 | Few or no visits | Cold |
| Year | 48° | 28° | 30.6 | 55.2 | 29,000 | |||
Year: average high and low, total precipitation and snowfall, total visitors. T = trace (under 0.05 in). – = not measured at this station. Updated .
- Hottest July, average high 74°F
- Coldest nights January, average low 1°F
- Source NOAA National Centers for Environmental Information; National Park Service
- Visitors a year about 29,000 (2023–2025 average)
- State Michigan
Closures, reservations and alerts: Isle Royale National Park on nps.gov
Nearby
- Grand Portage National MonumentBest: May, Jun and Sep · Minnesota
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