Weather on September 15 at Isle Royale
Isle Royale National Park
Based on 49 years of data from Houghton, MI
Planning Your Visit
September 15th in Isle Royale National Park (via Houghton, MI) typically brings mild fall weather, with average highs around 65°F and lows near 47°F. Over 49 years of records, the warmest September 15th was in 2015 (73°F average), while the coldest was 2011 (41°F) — a 32°F range across recorded history. Rain or other precipitation has occurred on about 37% of September 15th dates historically, with the wettest September 15th recording 2.06" of rain. The last decade has been 6.3°F warmer on this date compared to 20-30 years ago.
The last decade has been 6.3°F warmer on this date compared to 20-30 years ago.
Planning for September 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 |
|---|---|---|---|---|
| 2025 | 81°F | 58°F | 0" | -- |
| 2024 | 82°F | 65°F | 1.57" | -- |
| 2023 | 62°F | 57°F | 2.06" | -- |
| 2022 | 65°F | 46°F | 0.94" | -- |
| 2021 | 73°F | 49°F | 0" | -- |
| 2020 | 75°F | 56°F | 0" | -- |
| 2019 | 67°F | 51°F | 0.18" | -- |
| 2018 | 75°F | 62°F | 0" | -- |
| 2017 | 67°F | 58°F | 0.71" | -- |
| 2016 | 73°F | 43°F | 0" | -- |
| 2015 | 87°F | 59°F | 0" | -- |
| 2014 | 57°F | 41°F | 0" | -- |
| 2013 | 60°F | 37°F | 0.38" | -- |
| 2012 | 65°F | 35°F | 0" | -- |
| 2011 | 51°F | 31°F | 0" | -- |
| 2010 | 58°F | 36°F | 1.17" | -- |
| 2009 | 71°F | 51°F | 0" | -- |
| 2008 | 57°F | 46°F | 0" | -- |
| 2007 | 53°F | 33°F | 0" | -- |
| 2006 | 77°F | 47°F | 0" | -- |
| 2005 | 70°F | 39°F | 0" | -- |
| 2004 | 74°F | 58°F | 1.02" | -- |
| 2003 | 63°F | 47°F | 0" | -- |
| 2002 | 64°F | 44°F | 0" | 0" |
| 2001 | 67°F | 42°F | 0" | 0" |
| 2000 | 62°F | 43°F | 0" | 0" |
| 1999 | 63°F | 49°F | 0" | 0" |
| 1998 | 71°F | 60°F | 0.23" | 0" |
| 1997 | 68°F | 50°F | 0.28" | 0" |
| 1996 | 55°F | 49°F | 0" | 0" |
| 1995 | 62°F | 39°F | 0" | 0" |
| 1994 | 79°F | 60°F | 0.25" | 0" |
| 1993 | 53°F | 41°F | 0" | 0" |
| 1992 | 67°F | 46°F | 0" | 0" |
| 1991 | 76°F | 67°F | 0" | 0" |
| 1990 | 51°F | 42°F | 1.24" | 0" |
| 1989 | 71°F | 50°F | 0" | 0" |
| 1988 | 63°F | 43°F | 0" | 0" |
| 1983 | 60°F | 43°F | 0.43" | 0" |
| 1981 | 54°F | 44°F | 0.2" | 0" |
| 1980 | 61°F | 41°F | 0.08" | 0" |
| 1979 | 60°F | 48°F | 0.03" | 0" |
| 1978 | 58°F | 46°F | 0" | 0" |
| 1977 | 72°F | 50°F | 0" | 0" |
| 1976 | 58°F | 42°F | 0" | 0" |
| 1975 | 69°F | 53°F | 0" | 0" |
| 1974 | 56°F | 42°F | 0" | 0" |
| 1973 | 53°F | 45°F | 0.41" | 0" |
| 1971 | 64°F | 40°F | 0.05" | 0" |