Weather on August 21 at Biscayne
Biscayne National Park
Based on 55 years of data from Miami, FL
Planning Your Visit
August 21st in Biscayne National Park (via Miami, FL) typically brings warm summer weather, with average highs around 89°F and lows near 78°F. Over 55 years of records, the warmest August 21st was in 1983 (88°F average), while the coldest was 2006 (77°F) — a 11°F range across recorded history. Rain or other precipitation has occurred on about 51% of August 21st dates historically, with the wettest August 21st recording 7.49" of rain. The last decade has been 2.5°F warmer on this date compared to 20-30 years ago.
The last decade has been 2.5°F warmer on this date compared to 20-30 years ago.
Planning for August 21st in Biscayne? Stay hydrated and seek shade during peak afternoon hours. Consider bringing rain gear or an umbrella.
Year by Year History
| Year | High | Low | Precip | Snow |
|---|---|---|---|---|
| 2025 | 95°F | 79°F | 0" | -- |
| 2024 | 92°F | 81°F | 0" | -- |
| 2023 | 89°F | 80°F | 0.38" | -- |
| 2022 | 92°F | 83°F | 0.08" | -- |
| 2021 | 91°F | 78°F | 0" | -- |
| 2020 | 89°F | 80°F | 2.84" | -- |
| 2019 | 90°F | 82°F | 0" | -- |
| 2018 | 89°F | 82°F | 0" | -- |
| 2017 | 88°F | 77°F | 2.41" | -- |
| 2016 | 88°F | 80°F | 0" | -- |
| 2015 | 89°F | 82°F | 0" | -- |
| 2014 | 89°F | 80°F | 0" | -- |
| 2013 | 92°F | 80°F | 2.03" | -- |
| 2012 | 90°F | 79°F | 0" | -- |
| 2011 | 88°F | 76°F | 0" | -- |
| 2010 | 90°F | 78°F | 0" | 0" |
| 2009 | 89°F | 81°F | 0" | 0" |
| 2008 | 92°F | 72°F | 2.97" | 0" |
| 2007 | 88°F | 82°F | 0" | 0" |
| 2006 | 85°F | 70°F | 3.07" | -- |
| 2005 | 90°F | 78°F | 1.19" | 0" |
| 2004 | 93°F | 78°F | 1.32" | 0" |
| 2003 | 87°F | 72°F | 7.49" | 0" |
| 2002 | 88°F | 78°F | 0" | 0" |
| 2001 | 90°F | 78°F | 0.03" | 0" |
| 2000 | 88°F | 82°F | 0.05" | 0" |
| 1999 | 90°F | 78°F | 0.05" | 0" |
| 1998 | 89°F | 75°F | 0.48" | 0" |
| 1997 | 94°F | 72°F | 5.61" | 0" |
| 1996 | 85°F | 72°F | 1.96" | 0" |
| 1995 | 90°F | 82°F | 0" | 0" |
| 1994 | 90°F | 82°F | 0" | 0" |
| 1993 | 91°F | 81°F | 0" | 0" |
| 1992 | 89°F | 79°F | 0.1" | 0" |
| 1991 | 91°F | 78°F | 0.46" | 0" |
| 1990 | 90°F | 82°F | 0" | 0" |
| 1989 | 89°F | 79°F | 0" | 0" |
| 1988 | 87°F | 79°F | 0.94" | 0" |
| 1987 | 89°F | 81°F | 0" | 0" |
| 1986 | 87°F | 78°F | 0" | 0" |
| 1985 | 88°F | 76°F | 0.3" | 0" |
| 1984 | 90°F | 74°F | 4.19" | 0" |
| 1983 | 94°F | 82°F | 0" | 0" |
| 1982 | 87°F | 82°F | 0" | 0" |
| 1981 | 86°F | 75°F | 1.4" | 0" |
| 1980 | 95°F | 72°F | 5.59" | 0" |
| 1979 | 89°F | 77°F | 0.38" | 0" |
| 1978 | 86°F | 80°F | 0" | 0" |
| 1977 | 89°F | 76°F | 0.43" | 0" |
| 1976 | 86°F | 81°F | 0" | 0" |
| 1975 | 85°F | 76°F | 0.1" | 0" |
| 1974 | 88°F | 81°F | 0" | 0" |
| 1973 | 84°F | 75°F | 2.08" | 0" |
| 1972 | 87°F | 76°F | 0.76" | 0" |
| 1971 | 94°F | 77°F | 0" | 0" |