Weather on October 21
Sioux Falls, SD
55 Years of Data
Avg High
59°F
Avg Low
35°F
Warmest
2024
72°F avg
Coldest
1976
30°F avg
About This Date
October 21st in Sioux Falls, SD typically brings cool fall weather, with average highs around 59°F and lows near 35°F. Over 55 years of records, the warmest October 21st was in 2024 (72°F average), while the coldest was 1976 (30°F) — a 42°F range across recorded history. Rain or other precipitation has occurred on about 22% of October 21st dates historically, with the wettest October 21st recording 2.44" of rain. The last decade has been 5.2°F warmer on this date compared to 20-30 years ago.
The last decade has been 5.2°F warmer on this date compared to 20-30 years ago.
Planning for October 21st in Sioux Falls, SD? Bring layers as temperatures can vary throughout the day.
Warming Trend
0.9°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 51° | 30° | 41° | — | — |
| 2024warmest | 83° | 61° | 72° | — | — |
| 2023 | 68° | 40° | 54° | — | — |
| 2022 | 73° | 42° | 58° | — | — |
| 2021 | 53° | 38° | 45° | — | — |
| 2020 | 41° | 33° | 37° | 0.08" | — |
| 2019 | 51° | 42° | 47° | 1.12" | — |
| 2018 | 66° | 31° | 49° | — | — |
| 2017 | 73° | 43° | 58° | — | — |
| 2016 | 66° | 33° | 50° | — | — |
| 2015 | 60° | 37° | 49° | — | — |
| 2014 | 73° | 37° | 55° | — | — |
| 2013 | 50° | 33° | 42° | 0.03" | — |
| 2012 | 68° | 45° | 56° | — | — |
| 2011 | 67° | 27° | 47° | — | — |
| 2010 | 61° | 29° | 45° | — | — |
| 2009 | 47° | 39° | 43° | 2.44" | — |
| 2008 | 45° | 37° | 41° | 0.41" | — |
| 2007 | 54° | 46° | 50° | 0.2" | — |
| 2006 | 39° | 28° | 34° | — | — |
| 2005 | 57° | 33° | 45° | — | — |
| 2004 | 54° | 47° | 50° | 0.1" | — |
| 2003 | 75° | 39° | 57° | — | — |
| 2002 | 40° | 26° | 33° | — | — |
| 2001 | 64° | 36° | 50° | 0.05" | — |
| 2000 | 73° | 35° | 54° | — | — |
| 1999 | 71° | 37° | 54° | — | — |
| 1998 | 62° | 34° | 48° | — | — |
| 1997 | 43° | 22° | 32° | — | — |
| 1996 | 45° | 28° | 36° | — | — |
| 1995 | 51° | 26° | 39° | — | — |
| 1994 | 74° | 41° | 57° | 0.13" | — |
| 1993 | 54° | 29° | 41° | — | — |
| 1992 | 76° | 37° | 56° | — | — |
| 1991 | 70° | 35° | 52° | — | — |
| 1990 | 49° | 28° | 38° | — | — |
| 1989 | 71° | 22° | 46° | — | — |
| 1988 | 54° | 29° | 41° | — | — |
| 1987 | 45° | 20° | 32° | — | — |
| 1986 | 70° | 46° | 58° | — | — |
| 1985 | 56° | 41° | 48° | — | — |
| 1984 | 49° | 29° | 39° | — | — |
| 1983 | 49° | 43° | 46° | — | — |
| 1982 | 42° | 21° | 32° | — | — |
| 1981 | 44° | 25° | 34° | 0.03" | — |
| 1980 | 50° | 32° | 41° | — | — |
| 1979 | 47° | 36° | 41° | 0.15" | — |
| 1978 | 69° | 45° | 57° | — | — |
| 1977 | 65° | 41° | 53° | — | — |
| 1976coldest | 42° | 18° | 30° | — | — |
| 1975 | 66° | 34° | 50° | — | — |
| 1974 | 76° | 43° | 59° | — | — |
| 1973 | 76° | 49° | 62° | — | — |
| 1972 | 45° | 41° | 43° | 0.05" | — |
| 1971 | 67° | 37° | 52° | — | — |
55 years of data from SIOUX FALLS