Weather on December 21 at Isle Royale
Isle Royale National Park
Based on 50 years of data from Houghton, MI
Planning Your Visit
December 21st in Isle Royale National Park (via Houghton, MI) typically brings very cold winter weather, with average highs around 27°F and lows near 16°F. Over 50 years of records, the warmest December 21st was in 1994 (39°F average), while the coldest was 1989 (-4°F) — a 43°F range across recorded history. Precipitation has occurred on 58% of recorded December 21st dates, with snow falling 42% of the time (heaviest snowfall: 5.3"). The last decade has been 2.3°F warmer on this date compared to 20-30 years ago.
The last decade has been 2.3°F warmer on this date compared to 20-30 years ago.
Planning for December 21st in Isle Royale? Bundle up with warm layers and protect extremities from the cold. Consider bringing rain gear or an umbrella. Check road conditions if traveling, as snow is possible.
Year by Year History
| Year | High | Low | Precip | Snow |
|---|---|---|---|---|
| 2025 | 17°F | 9°F | 0" | -- |
| 2024 | 17°F | 6°F | 0" | -- |
| 2023 | 37°F | 29°F | 0" | -- |
| 2022 | 9°F | 3°F | 0.03" | -- |
| 2021 | 22°F | 14°F | 0.28" | -- |
| 2020 | 33°F | 22°F | 0.33" | -- |
| 2019 | 44°F | 29°F | 0" | -- |
| 2018 | 25°F | 20°F | 0" | -- |
| 2017 | 26°F | 14°F | 0" | -- |
| 2016 | 33°F | 25°F | 0.79" | -- |
| 2015 | 32°F | 24°F | 0" | -- |
| 2014 | 34°F | 26°F | 0.53" | -- |
| 2013 | 26°F | 14°F | 0" | -- |
| 2012 | 28°F | 20°F | 0.13" | -- |
| 2011 | 33°F | 27°F | 0" | -- |
| 2010 | 30°F | 20°F | 0" | -- |
| 2009 | 23°F | 15°F | 0.13" | -- |
| 2008 | 18°F | 5°F | 0.03" | -- |
| 2007 | 35°F | 31°F | 0" | -- |
| 2006 | 34°F | 16°F | 0" | -- |
| 2005 | 22°F | 17°F | 0" | -- |
| 2004 | 26°F | 10°F | 0.03" | -- |
| 2003 | 34°F | 16°F | 0" | -- |
| 2002 | 31°F | 27°F | 0" | 1.4" |
| 2001 | 28°F | 18°F | 0" | 0" |
| 2000 | 23°F | 11°F | 0.94" | 3.6" |
| 1999 | 14°F | 4°F | 1.83" | 5" |
| 1998 | 22°F | 10°F | 0.64" | 4.5" |
| 1997 | 33°F | 11°F | 0" | 0" |
| 1996 | 24°F | 12°F | 0.23" | 1.8" |
| 1995 | 24°F | 21°F | 0.1" | 0.4" |
| 1994 | 53°F | 24°F | 0" | 0" |
| 1993 | 26°F | 14°F | 0.2" | 1" |
| 1992 | 28°F | 6°F | 0.13" | 0.8" |
| 1991 | 36°F | 27°F | 0" | 0" |
| 1990 | 34°F | 19°F | 0.25" | 0.6" |
| 1989 | 1°F | -10°F | 0.53" | 5" |
| 1988 | 19°F | 10°F | 0.3" | 4.1" |
| 1987 | 29°F | 25°F | 0.08" | 0.3" |
| 1981 | 36°F | 21°F | 0.23" | 0.9" |
| 1980 | 15°F | 7°F | 0.05" | 1.3" |
| 1979 | 36°F | 27°F | 0" | 0" |
| 1978 | 29°F | 19°F | 0.64" | 4.9" |
| 1977 | 31°F | 23°F | 1.04" | 5.3" |
| 1976 | 12°F | 5°F | 0.33" | 1.6" |
| 1975 | 25°F | 10°F | 0" | 0" |
| 1974 | 26°F | 10°F | 0.08" | 0.8" |
| 1973 | 20°F | 2°F | 0.25" | 2.1" |
| 1972 | 28°F | 24°F | 0.15" | 1" |
| 1971 | 28°F | -1°F | 0.05" | 0.2" |