Weather on September 21
Santa Clara, CA
55 Years of Data
Avg High
81°F
Avg Low
56°F
Warmest
2015
80°F avg
Coldest
1975
61°F avg
About This Date
September 21st in Santa Clara, CA typically brings warm fall weather, with average highs around 81°F and lows near 56°F — a 25°F daily swing. Over 55 years of records, the warmest September 21st was in 2015 (80°F average), while the coldest was 1975 (61°F) — a 19°F range across recorded history. Rain or other precipitation has occurred on about 2% of September 21st dates historically, with the wettest September 21st recording 1.68" of rain. Temperatures on this date have remained relatively stable over the past several decades.
Temperatures on this date have remained relatively stable over the past several decades.
Planning for September 21st in Santa Clara, CA? Stay hydrated and seek shade during peak afternoon hours.
Warming Trend
0.9°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 79° | 61° | 70° | — | — |
| 2024 | 82° | 57° | 70° | — | — |
| 2023 | 81° | 56° | 68° | — | — |
| 2022 | 75° | 62° | 69° | — | — |
| 2021 | 92° | 61° | 76° | — | — |
| 2020 | 83° | 60° | 71° | — | — |
| 2019 | 87° | 58° | 72° | — | — |
| 2018 | 85° | 57° | 71° | — | — |
| 2017 | 72° | 54° | 63° | — | — |
| 2016 | 76° | 58° | 67° | — | — |
| 2015warmest | 97° | 64° | 80° | — | — |
| 2014 | 74° | 62° | 68° | — | — |
| 2013 | 70° | 57° | 63° | 1.68" | — |
| 2012 | 79° | 51° | 65° | — | — |
| 2011 | 93° | 60° | 77° | — | — |
| 2010 | 73° | 54° | 63° | — | — |
| 2009 | 89° | 59° | 74° | — | — |
| 2008 | 74° | 56° | 65° | — | — |
| 2007 | — | 58° | — | — | — |
| 2006 | 79° | 58° | 68° | — | — |
| 2005 | 78° | 57° | 68° | — | — |
| 2004 | 81° | 50° | 65° | — | — |
| 2003 | 97° | 62° | 79° | — | — |
| 2002 | 91° | 60° | 76° | — | — |
| 2001 | 77° | 57° | 67° | — | — |
| 2000 | 75° | 61° | 68° | — | — |
| 1999 | 78° | 55° | 67° | — | — |
| 1998 | 76° | 55° | 65° | — | — |
| 1997 | 88° | 57° | 72° | — | — |
| 1996 | 87° | 57° | 72° | — | — |
| 1995 | 79° | 61° | 70° | — | — |
| 1994 | 81° | 61° | 71° | — | — |
| 1993 | 77° | 53° | 65° | — | — |
| 1992 | 81° | 55° | 68° | — | — |
| 1991 | 88° | 55° | 71° | — | — |
| 1990 | 86° | 58° | 72° | — | — |
| 1989 | 83° | 54° | 68° | — | — |
| 1988 | 76° | 53° | 64° | — | — |
| 1987 | 88° | 56° | 72° | — | — |
| 1986 | 73° | 48° | 61° | — | — |
| 1985 | 86° | 53° | 70° | — | — |
| 1984 | 82° | 56° | 69° | — | — |
| 1983 | 91° | 67° | 79° | — | — |
| 1982 | 84° | 51° | 68° | — | — |
| 1981 | 81° | 52° | 66° | — | — |
| 1980 | 78° | 50° | 64° | — | — |
| 1979 | 82° | 55° | 69° | — | — |
| 1978 | 80° | 51° | 66° | — | — |
| 1977 | 79° | 52° | 65° | — | — |
| 1976 | 74° | 55° | 64° | — | — |
| 1975coldest | 72° | 50° | 61° | — | — |
| 1974 | 74° | 50° | 62° | — | — |
| 1973 | 79° | 50° | 64° | — | — |
| 1972 | 85° | 49° | 67° | — | — |
| 1971 | 78° | 56° | 67° | — | — |
55 years of data from SANTA CLARA UNIV