Weather on September 21 at Indiana Dunes
Indiana Dunes National Park
Based on 55 years of data from Gary, IN
Planning Your Visit
September 21st in Indiana Dunes National Park (via Gary, IN) typically brings pleasant fall weather, with average highs around 74°F and lows near 53°F. Over 55 years of records, the warmest September 21st was in 2017 (80°F average), while the coldest was 1995 (44°F) — a 36°F range across recorded history. Rain or other precipitation has occurred on about 36% of September 21st dates historically, with the wettest September 21st recording 2.79" of rain. The last decade has been 10.9°F warmer on this date compared to 20-30 years ago.
The last decade has been 10.9°F warmer on this date compared to 20-30 years ago.
Planning for September 21st in Indiana Dunes? Great weather for outdoor activities. Consider bringing rain gear or an umbrella.
Year by Year History
| Year | High | Low | Precip | Snow |
|---|---|---|---|---|
| 2025 | 80°F | 64°F | 0.13" | 0" |
| 2024 | 85°F | 58°F | 0" | 0" |
| 2023 | 80°F | 60°F | 0" | 0" |
| 2022 | 84°F | 62°F | 0.03" | 0" |
| 2021 | 80°F | 66°F | 0.15" | 0" |
| 2020 | 78°F | 49°F | -- | -- |
| 2019 | 80°F | 69°F | -- | -- |
| 2018 | 90°F | 64°F | 0.53" | -- |
| 2017 | 91°F | 68°F | 0" | 0" |
| 2016 | 79°F | 64°F | 0" | 0" |
| 2015 | 70°F | 51°F | 0" | 0" |
| 2014 | 78°F | 58°F | 0.74" | 0" |
| 2013 | 74°F | 59°F | 0" | 0" |
| 2012 | 68°F | 45°F | 0" | 0" |
| 2011 | 75°F | 55°F | 0" | 0" |
| 2010 | 76°F | 61°F | 0.03" | 0" |
| 2009 | 77°F | 60°F | 0.05" | 0" |
| 2008 | 78°F | 57°F | 0" | 0" |
| 2007 | 75°F | 64°F | 0" | 0" |
| 2006 | 58°F | 41°F | 0" | 0" |
| 2005 | 77°F | 56°F | 0" | 0" |
| 2004 | 80°F | 53°F | 0" | 0" |
| 2003 | 67°F | 44°F | 0" | 0" |
| 2002 | 71°F | 59°F | 0.69" | 0" |
| 2001 | 74°F | 57°F | 0.15" | 0" |
| 2000 | 64°F | 45°F | 1.09" | 0" |
| 1999 | 67°F | 38°F | 0" | 0" |
| 1998 | 89°F | 65°F | 2.79" | 0" |
| 1997 | 65°F | 45°F | 0" | 0" |
| 1996 | 73°F | 47°F | 0" | 0" |
| 1995 | 53°F | 36°F | 0.58" | 0" |
| 1994 | 84°F | 54°F | 0" | 0" |
| 1993 | 65°F | 57°F | 0.05" | 0" |
| 1992 | 76°F | 55°F | 0.86" | 0" |
| 1991 | 68°F | 35°F | 0" | 0" |
| 1990 | 72°F | 55°F | 1.93" | 0" |
| 1989 | 78°F | 53°F | 0" | 0" |
| 1988 | 67°F | 51°F | 0" | 0" |
| 1987 | 62°F | 48°F | 0.28" | 0" |
| 1986 | 84°F | 55°F | 0" | 0" |
| 1985 | 85°F | 55°F | 0" | 0" |
| 1984 | 85°F | 49°F | 0" | 0" |
| 1983 | 55°F | 41°F | 0.41" | 0" |
| 1982 | 56°F | 42°F | 0.76" | 0" |
| 1981 | 78°F | 50°F | 0" | 0" |
| 1980 | 88°F | 70°F | 0" | 0" |
| 1979 | 76°F | 56°F | 0" | 0" |
| 1978 | 90°F | 49°F | 0" | 0" |
| 1977 | 61°F | 53°F | 0" | 0" |
| 1976 | 78°F | 44°F | 0" | 0" |
| 1975 | 57°F | 50°F | 0.13" | 0" |
| 1974 | 66°F | 52°F | 0" | 0" |
| 1973 | 73°F | 42°F | 0" | 0" |
| 1972 | 80°F | 58°F | 0.15" | 0" |
| 1971 | 70°F | 41°F | 0" | 0" |