Weather on September 21 at Great Sand Dunes
Great Sand Dunes National Park and Preserve
Based on 55 years of data from Alamosa, CO
Elevation Note: Great Sand Dunes sits at 8,200 ft. Expect temperatures 29°F cooler than the data shown below, which comes from Alamosa, CO at a lower elevation.
Planning Your Visit
September 21st in Great Sand Dunes National Park (via Alamosa, CO) typically brings pleasant fall weather, with average highs around 72°F and lows near 35°F — a 37°F daily swing. Over 55 years of records, the warmest September 21st was in 2014 (66°F average), while the coldest was 1978 (42°F) — a 24°F range across recorded history. Rain or other precipitation has occurred on about 18% of September 21st dates historically, with the wettest September 21st recording 0.91" of rain. The last decade has been 3.2°F warmer on this date compared to 20-30 years ago.
The last decade has been 3.2°F warmer on this date compared to 20-30 years ago.
Planning for September 21st in Great Sand Dunes? Great weather for outdoor activities.
Year by Year History
| Year | High | Low | Precip | Snow |
|---|---|---|---|---|
| 2025 | 75°F | 38°F | 0" | 0" |
| 2024 | 80°F | 34°F | 0" | 0" |
| 2023 | 71°F | 32°F | 0.05" | 0" |
| 2022 | 80°F | 38°F | 0.48" | 0" |
| 2021 | 78°F | 31°F | 0" | 0" |
| 2020 | 79°F | 38°F | 0" | 0" |
| 2019 | 74°F | 38°F | 0" | 0" |
| 2018 | 72°F | 38°F | 0.13" | 0" |
| 2017 | 75°F | 41°F | 0" | 0" |
| 2016 | 80°F | 44°F | 0" | 0" |
| 2015 | 79°F | 33°F | 0" | 0" |
| 2014 | 84°F | 49°F | 0" | 0" |
| 2013 | 73°F | 37°F | 0" | 0" |
| 2012 | 77°F | 28°F | 0" | 0" |
| 2011 | 73°F | 34°F | 0" | -- |
| 2010 | 82°F | 44°F | 0" | 0" |
| 2009 | 73°F | 33°F | 0.71" | 0" |
| 2008 | 75°F | 35°F | 0" | 0" |
| 2007 | 67°F | 41°F | 0.56" | 0" |
| 2006 | 58°F | 38°F | 0.18" | 0" |
| 2005 | 80°F | 30°F | -- | 0" |
| 2004 | 65°F | 43°F | 0" | 0" |
| 2003 | 73°F | 29°F | 0" | 0" |
| 2002 | 73°F | 31°F | 0" | 0" |
| 2001 | 77°F | 33°F | 0" | 0" |
| 2000 | 77°F | 46°F | 0.15" | 0" |
| 1999 | 65°F | 32°F | 0" | 0" |
| 1998 | 74°F | 38°F | 0" | 0" |
| 1997 | 59°F | 46°F | 0.91" | 0" |
| 1996 | 72°F | 26°F | 0" | 0" |
| 1995 | 54°F | 30°F | 0.58" | 0" |
| 1994 | 70°F | 31°F | 0" | 0" |
| 1993 | 78°F | 37°F | 0" | 0" |
| 1992 | 66°F | 32°F | 0" | 0" |
| 1991 | 77°F | 32°F | 0" | 0" |
| 1990 | 70°F | 36°F | 0" | 0" |
| 1989 | 71°F | 27°F | 0" | 0" |
| 1988 | 67°F | 43°F | 0.05" | 0" |
| 1987 | 71°F | 37°F | 0" | 0" |
| 1986 | 76°F | 37°F | 0" | 0" |
| 1985 | 61°F | 36°F | 0" | 0" |
| 1984 | 76°F | 40°F | 0" | 0" |
| 1983 | 70°F | 18°F | 0" | 0" |
| 1982 | 68°F | 36°F | 0" | 0" |
| 1981 | 78°F | 34°F | 0" | 0" |
| 1980 | 75°F | 33°F | 0" | 0" |
| 1979 | 68°F | 42°F | 0" | 0" |
| 1978 | 67°F | 17°F | 0" | 0" |
| 1977 | 71°F | 37°F | 0" | 0" |
| 1976 | 72°F | 32°F | 0" | 0" |
| 1975 | 58°F | 35°F | 0" | 0" |
| 1974 | 70°F | 38°F | 0" | 0" |
| 1973 | 78°F | 35°F | 0" | 0" |
| 1972 | 68°F | 35°F | 0" | 0" |
| 1971 | 63°F | 38°F | 0" | 0" |