Weather on May 21 at Isle Royale
Isle Royale National Park
MIMidwest800 ft elevation
Avg High66°F
Avg Low44°F
Warmest197474°F
Coldest200639°F
Based on 50 years of data from Houghton, MI
Planning Your Visit
May 21st in Isle Royale National Park (via Houghton, MI) typically brings mild spring weather, with average highs around 66°F and lows near 44°F. Over 50 years of records, the warmest May 21st was in 1974 (74°F average), while the coldest was 2006 (39°F) — a 35°F range across recorded history. Rain or other precipitation has occurred on about 28% of May 21st dates historically, with the wettest May 21st recording 2.49" of rain. The last decade has been 2.7°F warmer on this date compared to 20-30 years ago.
The last decade has been 2.7°F warmer on this date compared to 20-30 years ago.
Planning for May 21st in Isle Royale? Great weather for outdoor activities.
Year by Year History
| Year | High | Low | Precip | Snow |
|---|---|---|---|---|
| 2025 | 60°F | 43°F | 0" | -- |
| 2024 | 62°F | 49°F | 1.42" | -- |
| 2023 | 58°F | 47°F | 0" | -- |
| 2022 | 52°F | 39°F | 0" | -- |
| 2021 | 73°F | 65°F | 2.49" | -- |
| 2020 | 78°F | 46°F | 0" | -- |
| 2019 | 63°F | 36°F | 0" | -- |
| 2018 | 74°F | 43°F | 0" | -- |
| 2017 | 53°F | 41°F | 0.71" | -- |
| 2016 | 76°F | 44°F | 0" | -- |
| 2015 | 59°F | 34°F | 0" | -- |
| 2014 | 61°F | 42°F | 0.15" | -- |
| 2013 | 48°F | 43°F | 2.11" | -- |
| 2012 | 64°F | 41°F | 0" | -- |
| 2011 | 60°F | 48°F | 0.64" | -- |
| 2010 | 74°F | 48°F | 0" | -- |
| 2009 | 78°F | 42°F | 0.05" | -- |
| 2008 | 53°F | 37°F | 0" | -- |
| 2007 | 53°F | 34°F | 0.25" | -- |
| 2006 | 47°F | 32°F | 0" | -- |
| 2005 | 75°F | 44°F | 0" | -- |
| 2004 | 49°F | 38°F | 0" | -- |
| 2003 | 63°F | 34°F | 0" | 0" |
| 2002 | 62°F | 29°F | 0" | 0" |
| 2001 | 80°F | 50°F | 0.99" | 0" |
| 2000 | 68°F | 34°F | 0" | 0" |
| 1999 | 66°F | 52°F | 0.58" | 0" |
| 1998 | 66°F | 39°F | 0" | 0" |
| 1997 | 51°F | 33°F | 0" | 0" |
| 1996 | 68°F | 43°F | 0" | 0" |
| 1995 | 56°F | 40°F | 0.69" | 0" |
| 1994 | 87°F | 49°F | 0" | 0" |
| 1993 | 57°F | 39°F | 0" | 0" |
| 1992 | 88°F | 61°F | 0" | 0" |
| 1991 | 83°F | 59°F | 0" | 0" |
| 1990 | 60°F | 38°F | 0" | 0" |
| 1989 | 71°F | 51°F | 0" | 0" |
| 1988 | 73°F | 51°F | 0" | 0" |
| 1982 | 51°F | 35°F | 0" | 0" |
| 1981 | 79°F | 55°F | 0" | 0" |
| 1980 | 82°F | 62°F | 0" | 0" |
| 1979 | 55°F | 35°F | 0" | 0" |
| 1978 | 64°F | 34°F | 0" | 0" |
| 1977 | 71°F | 54°F | 0.25" | 0" |
| 1976 | 55°F | 41°F | 0" | 0" |
| 1975 | 80°F | 55°F | 0.1" | 0" |
| 1974 | 89°F | 59°F | 0.89" | 0" |
| 1973 | 66°F | 37°F | 0" | 0" |
| 1972 | 65°F | 47°F | 0" | 0" |
| 1971 | 53°F | 35°F | 0" | 0" |
May 21 at Nearby Parks
Holiday Weather at Isle Royale
Official NPS WebsiteVisit nps.gov/isro for park information, alerts, and reservations
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