Weather on September 20 at Isle Royale
Isle Royale National Park
Based on 50 years of data from Houghton, MI
Planning Your Visit
September 20th in Isle Royale National Park (via Houghton, MI) typically brings mild fall weather, with average highs around 65°F and lows near 48°F. Over 50 years of records, the warmest September 20th was in 2021 (74°F average), while the coldest was 1973 (42°F) — a 32°F range across recorded history. Rain or other precipitation has occurred on about 48% of September 20th dates historically, with the wettest September 20th recording 4.34" of rain. The last decade has been 4.9°F warmer on this date compared to 20-30 years ago.
The last decade has been 4.9°F warmer on this date compared to 20-30 years ago.
Planning for September 20th 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 | 68°F | 57°F | 0" | -- |
| 2024 | 78°F | 58°F | 0.08" | -- |
| 2023 | 75°F | 56°F | 0" | -- |
| 2022 | 81°F | 52°F | 0" | -- |
| 2021 | 83°F | 66°F | 1.85" | -- |
| 2020 | 70°F | 45°F | 0" | -- |
| 2019 | 69°F | 59°F | 0" | -- |
| 2018 | 60°F | 53°F | 4.34" | -- |
| 2017 | 73°F | 55°F | 0.03" | -- |
| 2016 | 75°F | 55°F | 0" | -- |
| 2015 | 74°F | 56°F | 0" | -- |
| 2014 | 67°F | 53°F | 0" | -- |
| 2013 | 67°F | 50°F | 0.05" | -- |
| 2012 | 55°F | 41°F | 0.79" | -- |
| 2011 | 70°F | 45°F | 0.1" | -- |
| 2010 | 60°F | 33°F | 0" | -- |
| 2009 | 75°F | 54°F | 0" | -- |
| 2008 | 68°F | 39°F | 0" | -- |
| 2007 | 62°F | 39°F | 0.1" | -- |
| 2006 | 53°F | 42°F | 0" | -- |
| 2005 | 76°F | 48°F | 0" | -- |
| 2004 | 77°F | 60°F | 0" | -- |
| 2003 | 61°F | 48°F | 0" | -- |
| 2002 | 71°F | 58°F | 0.36" | 0" |
| 2001 | 64°F | 61°F | 0" | 0" |
| 2000 | 67°F | 49°F | 0.03" | 0" |
| 1999 | 55°F | 43°F | 0.3" | 0" |
| 1998 | 73°F | 60°F | 0" | 0" |
| 1997 | 62°F | 45°F | 0.48" | 0" |
| 1996 | 70°F | 43°F | 0" | 0" |
| 1995 | 54°F | 35°F | 0.08" | 0" |
| 1994 | 79°F | 57°F | 0" | 0" |
| 1993 | 54°F | 43°F | 0" | 0" |
| 1992 | 72°F | 49°F | 0" | 0" |
| 1991 | 52°F | 37°F | 0.03" | 0" |
| 1990 | 58°F | 45°F | 0.08" | 0" |
| 1989 | 69°F | 59°F | 0.36" | 0" |
| 1988 | 61°F | 48°F | 0.08" | 0" |
| 1983 | 50°F | 45°F | 0.58" | 0" |
| 1981 | 52°F | 39°F | 0" | 0" |
| 1980 | 59°F | 43°F | 0" | 0" |
| 1979 | 60°F | 51°F | 0" | 0" |
| 1978 | 56°F | 48°F | 0.03" | 0" |
| 1977 | 50°F | 42°F | 0.05" | 0" |
| 1976 | 58°F | 42°F | 0.38" | 0" |
| 1975 | 54°F | 47°F | 0.76" | 0" |
| 1974 | 51°F | 35°F | 0.18" | 0" |
| 1973 | 48°F | 35°F | 0" | 0" |
| 1972 | 72°F | 55°F | 1.93" | 0" |
| 1971 | 65°F | 41°F | 0" | 0" |