Weather on May 15 at Isle Royale
Isle Royale National Park
MIMidwest800 ft elevation
Avg High63°F
Avg Low41°F
Warmest199872°F
Coldest199738°F
Based on 51 years of data from Houghton, MI
Planning Your Visit
May 15th in Isle Royale National Park (via Houghton, MI) typically brings mild spring weather, with average highs around 63°F and lows near 41°F. Over 51 years of records, the warmest May 15th was in 1998 (72°F average), while the coldest was 1997 (38°F) — a 34°F range across recorded history. Precipitation has occurred on 39% of recorded May 15th dates, with snow falling 2% of the time. The last decade has been 2.8°F warmer on this date compared to 20-30 years ago.
The last decade has been 2.8°F warmer on this date compared to 20-30 years ago.
Planning for May 15th in Isle Royale? Great weather for outdoor activities. Consider bringing rain gear or an umbrella.
Year by Year History
| Year | High | Low | Precip | Snow |
|---|---|---|---|---|
| 2026 | 84°F | 50°F | 0.23" | -- |
| 2025 | 70°F | 59°F | 3" | -- |
| 2024 | 60°F | 34°F | 0" | -- |
| 2023 | 74°F | 39°F | 0" | -- |
| 2022 | 71°F | 46°F | 0" | -- |
| 2021 | 68°F | 46°F | 0" | -- |
| 2020 | 59°F | 40°F | 0.71" | -- |
| 2019 | 56°F | 41°F | 0" | -- |
| 2018 | 56°F | 36°F | 0" | -- |
| 2017 | 65°F | 40°F | 0.2" | -- |
| 2016 | 54°F | 35°F | 0.84" | -- |
| 2015 | 52°F | 42°F | 0.56" | -- |
| 2014 | 43°F | 33°F | 0" | -- |
| 2013 | 70°F | 44°F | 0" | -- |
| 2012 | 66°F | 40°F | 0.15" | -- |
| 2011 | 51°F | 35°F | 0" | -- |
| 2010 | 61°F | 32°F | 0" | -- |
| 2009 | 61°F | 29°F | 0.03" | -- |
| 2008 | 67°F | 38°F | 0" | -- |
| 2007 | 48°F | 40°F | 0.03" | -- |
| 2006 | 64°F | 42°F | 0.08" | -- |
| 2005 | 43°F | 35°F | 0.18" | -- |
| 2004 | 50°F | 34°F | 0" | -- |
| 2003 | 64°F | 41°F | 0" | 0" |
| 2002 | 72°F | 30°F | 0.03" | 0" |
| 2001 | 66°F | 50°F | 0" | 0" |
| 2000 | 62°F | 36°F | 0" | 0" |
| 1999 | 71°F | 43°F | 0" | 0" |
| 1998 | 87°F | 58°F | 0" | 0" |
| 1997 | 45°F | 32°F | 0.25" | 0" |
| 1996 | 58°F | 39°F | 0.03" | 0" |
| 1995 | 57°F | 36°F | 0" | 0" |
| 1994 | 64°F | 38°F | 1.02" | 0" |
| 1993 | 47°F | 38°F | 0.2" | 0" |
| 1992 | 65°F | 46°F | 0" | 0" |
| 1991 | 89°F | 51°F | 0.15" | 0" |
| 1990 | 55°F | 42°F | 0" | 0" |
| 1989 | 71°F | 50°F | 0" | 0" |
| 1988 | 73°F | 39°F | 0.13" | 0" |
| 1982 | 76°F | 52°F | 0" | 0" |
| 1981 | 67°F | 44°F | 0" | 0" |
| 1980 | 59°F | 40°F | 0" | 0" |
| 1979 | 49°F | 37°F | 0" | 0" |
| 1978 | 66°F | 38°F | 0" | 0" |
| 1977 | 80°F | 52°F | 0" | 0" |
| 1976 | 73°F | 43°F | 0" | 0" |
| 1975 | 46°F | 33°F | 0.71" | 0" |
| 1974 | 54°F | 34°F | 0" | 0" |
| 1973 | 68°F | 33°F | 0.28" | 0.3" |
| 1972 | 66°F | 37°F | 0" | 0" |
| 1971 | 73°F | 53°F | 0" | 0" |
May 15 at Nearby Parks
Holiday Weather at Isle Royale
Official NPS WebsiteVisit nps.gov/isro for park information, alerts, and reservations
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