Weather on September 21
Hayward, CA
55 Years of Data
Avg High
77°F
Avg Low
56°F
Warmest
1983
80°F avg
Coldest
1971
57°F avg
About This Date
September 21st in Hayward, CA typically brings pleasant fall weather, with average highs around 77°F and lows near 56°F. Over 53 years of records, the warmest September 21st was in 1983 (80°F average), while the coldest was 1971 (57°F) — a 23°F range across recorded history. Rain or other precipitation has occurred on about 8% of September 21st dates historically, with the wettest September 21st recording 0.56" 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 Hayward, CA? Great weather for outdoor activities.
Warming Trend
1.0°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 77° | 61° | 69° | — | — |
| 2024 | 75° | 59° | 67° | — | — |
| 2023 | 76° | 57° | 66° | — | — |
| 2022 | 73° | 59° | 66° | 0.05" | — |
| 2021 | 93° | 60° | 77° | — | — |
| 2020 | 79° | 58° | 68° | — | — |
| 2019 | 86° | 58° | 72° | — | — |
| 2018 | 81° | 57° | 69° | — | — |
| 2017 | 68° | 55° | 62° | — | — |
| 2016 | 68° | 56° | 62° | — | — |
| 2015 | 94° | 61° | 77° | — | — |
| 2014 | 72° | 66° | 69° | — | — |
| 2013 | 64° | 56° | 60° | 0.56" | — |
| 2012 | 74° | 54° | 64° | — | — |
| 2011 | 86° | 57° | 72° | — | — |
| 2010 | 67° | 59° | 63° | — | — |
| 2009 | 81° | 57° | 69° | — | — |
| 2008 | 68° | 57° | 63° | — | — |
| 2007 | 74° | 57° | 65° | — | — |
| 2006 | 76° | 58° | 67° | — | — |
| 2005 | 73° | 56° | 64° | — | — |
| 2004 | 78° | 53° | 66° | — | — |
| 2003 | 97° | 64° | 80° | — | — |
| 2002 | 81° | 59° | 70° | — | — |
| 2001 | 69° | 54° | 61° | — | — |
| 2000 | 74° | 62° | 68° | — | — |
| 1999 | 73° | 56° | 64° | 0.05" | — |
| 1998 | 68° | 56° | 62° | — | — |
| 1997 | 84° | 56° | 70° | — | — |
| 1996 | 79° | 53° | 66° | — | — |
| 1995 | 70° | 54° | 62° | — | — |
| 1994 | 73° | 53° | 63° | — | — |
| 1993 | 68° | 50° | 59° | — | — |
| 1992 | 76° | 53° | 64° | — | — |
| 1989 | 74° | 51° | 62° | — | — |
| 1988 | 74° | 50° | 62° | — | — |
| 1987 | 88° | 51° | 69° | — | — |
| 1986 | 70° | 51° | 60° | — | — |
| 1985 | 76° | 54° | 65° | — | — |
| 1984 | 85° | 55° | 70° | — | — |
| 1983warmest | 93° | 66° | 80° | — | — |
| 1982 | 80° | 54° | 67° | — | — |
| 1981 | 78° | 54° | 66° | — | — |
| 1980 | 71° | 53° | 62° | — | — |
| 1979 | 82° | 56° | 69° | — | — |
| 1978 | 83° | 50° | 66° | — | — |
| 1977 | 74° | 54° | 64° | — | — |
| 1976 | 70° | 56° | 63° | — | — |
| 1975 | 73° | 50° | 62° | — | — |
| 1974 | 71° | 53° | 62° | — | — |
| 1973 | 72° | 49° | 60° | 0.46" | — |
| 1972 | 80° | 47° | 63° | — | — |
| 1971coldest | 66° | 49° | 57° | — | — |
53 years of data from HAYWARD AIR TERMINAL