Weather on September 21 at Acadia
Acadia National Park
Based on 53 years of data from Bar Harbor, ME
Planning Your Visit
September 21st in Acadia National Park (via Bar Harbor, ME) typically brings mild fall weather, with average highs around 68°F and lows near 50°F. Over 53 years of records, the warmest September 21st was in 1983 (71°F average), while the coldest was 1991 (45°F) — a 26°F range across recorded history. Rain or other precipitation has occurred on about 32% of September 21st dates historically, with the wettest September 21st recording 12.37" of rain. The last decade has been 1.1°F cooler on this date compared to 20-30 years ago.
The last decade has been 1.1°F cooler on this date compared to 20-30 years ago.
Planning for September 21st in Acadia? Great weather for outdoor activities. Consider bringing rain gear or an umbrella.
Year by Year History
| Year | High | Low | Precip | Snow |
|---|---|---|---|---|
| 2025 | 66°F | 49°F | -- | -- |
| 2024 | 65°F | 54°F | -- | -- |
| 2023 | 70°F | 53°F | -- | -- |
| 2022 | 65°F | 50°F | -- | -- |
| 2021 | 69°F | 49°F | -- | -- |
| 2020 | 63°F | 43°F | -- | -- |
| 2019 | 76°F | 59°F | -- | -- |
| 2018 | 62°F | 50°F | -- | -- |
| 2017 | 72°F | 55°F | -- | -- |
| 2016 | 80°F | 60°F | -- | -- |
| 2015 | 69°F | 46°F | -- | -- |
| 2014 | 71°F | 58°F | -- | -- |
| 2013 | 66°F | 54°F | -- | -- |
| 2012 | 63°F | 49°F | 0" | -- |
| 2011 | 73°F | 54°F | 0.03" | -- |
| 2010 | 66°F | 43°F | 0" | 0" |
| 2009 | 71°F | 47°F | 0" | 0" |
| 2008 | 66°F | 47°F | 0" | 0" |
| 2007 | 72°F | 57°F | 0" | 0" |
| 2006 | 69°F | 51°F | 0.03" | 0" |
| 2005 | 72°F | 53°F | 0.33" | 0" |
| 2004 | 66°F | 50°F | 0" | 0" |
| 2003 | 74°F | 58°F | 0" | 0" |
| 2002 | 72°F | 62°F | 0" | 0" |
| 2001 | 67°F | 56°F | 0.03" | 0" |
| 1999 | 73°F | 56°F | 0" | 0" |
| 1997 | 70°F | 39°F | 0.46" | 0" |
| 1996 | 71°F | 47°F | 0" | 0" |
| 1995 | 69°F | 44°F | 0" | 0" |
| 1994 | 73°F | 54°F | 0" | 0" |
| 1993 | 63°F | 35°F | 0" | 0" |
| 1992 | 68°F | 43°F | 0" | 0" |
| 1991 | 57°F | 34°F | 0.05" | 0" |
| 1990 | 63°F | 39°F | 0.08" | 0" |
| 1989 | 77°F | 56°F | 0.91" | 0" |
| 1988 | 66°F | 53°F | 2.57" | 0" |
| 1987 | 54°F | 51°F | 12.37" | 0" |
| 1986 | 62°F | 45°F | 2.03" | 0" |
| 1985 | 82°F | 61°F | 0" | 0" |
| 1984 | 69°F | 42°F | 0" | 0" |
| 1983 | 78°F | 64°F | 0" | 0" |
| 1982 | 64°F | 47°F | 0.84" | 0" |
| 1981 | 61°F | 46°F | 0" | 0" |
| 1980 | 70°F | 57°F | 0" | 0" |
| 1979 | 69°F | 38°F | 0" | 0" |
| 1978 | 81°F | 56°F | 0" | 0" |
| 1977 | 56°F | 44°F | 2.54" | 0" |
| 1976 | 73°F | 61°F | 0.18" | 0" |
| 1975 | 65°F | 54°F | 0.05" | 0" |
| 1974 | 65°F | 56°F | 0.03" | 0" |
| 1973 | 62°F | 36°F | 0" | 0" |
| 1972 | 65°F | 41°F | 0" | 0" |
| 1971 | 70°F | 58°F | 0.08" | 0" |