Weather on September 21
San Bernardino, CA
55 Years of Data
Avg High
89°F
Avg Low
59°F
Warmest
2003
85°F avg
Coldest
2017
58°F avg
About This Date
September 21st in San Bernardino, CA typically brings warm fall weather, with average highs around 89°F and lows near 59°F — a 30°F daily swing. Over 47 years of records, the warmest September 21st was in 2003 (85°F average), while the coldest was 2017 (58°F) — a 27°F range across recorded history. Rain or other precipitation has occurred on about 2% of September 21st dates historically.
Planning for September 21st in San Bernardino, CA? Stay hydrated and seek shade during peak afternoon hours.
Cooling Trend
0.7°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2017coldest | 64° | 52° | 58° | — | — |
| 2016 | 84° | 66° | 75° | — | — |
| 2015 | 96° | 68° | 82° | — | — |
| 2014 | 83° | 64° | 73° | — | — |
| 2013 | 77° | 61° | 69° | — | — |
| 2012 | 101° | 64° | 82° | — | — |
| 2011 | 96° | 58° | 77° | — | — |
| 2010 | 80° | 52° | 66° | — | — |
| 2009 | 95° | 59° | 77° | — | — |
| 2008 | 82° | 53° | 68° | — | — |
| 2007 | 85° | 46° | 65° | — | — |
| 2006 | 77° | 52° | 64° | — | — |
| 2005 | 93° | 58° | 75° | — | — |
| 2004 | 89° | 55° | 72° | — | — |
| 2003warmest | 109° | 61° | 85° | — | — |
| 2002 | 98° | 56° | 77° | — | — |
| 2001 | 92° | 58° | 75° | — | — |
| 2000 | 84° | 65° | 74° | — | — |
| 1999 | 99° | 63° | 81° | — | — |
| 1998 | 71° | 60° | 66° | — | — |
| 1997 | 94° | 57° | 75° | — | — |
| 1996 | 89° | 57° | 73° | — | — |
| 1995 | 95° | 57° | 76° | — | — |
| 1994 | 92° | 57° | 74° | — | — |
| 1993 | 78° | 61° | 69° | — | — |
| 1992 | 102° | 59° | 81° | — | — |
| 1991 | 87° | 64° | 76° | — | — |
| 1990 | 81° | 62° | 71° | — | — |
| 1989 | 99° | 66° | 82° | — | — |
| 1988 | 68° | 53° | 61° | 0.03" | — |
| 1987 | 93° | 61° | 77° | — | — |
| 1986 | 78° | 48° | 63° | — | — |
| 1985 | 89° | 56° | 72° | — | — |
| 1984 | 85° | 65° | 75° | — | — |
| 1983 | 96° | 65° | 80° | — | — |
| 1982 | 101° | 58° | 79° | — | — |
| 1981 | 95° | 61° | 78° | — | — |
| 1980 | 81° | 62° | 71° | — | — |
| 1979 | 100° | 61° | 80° | — | — |
| 1978 | 92° | 48° | 70° | — | — |
| 1977 | 91° | 51° | 71° | — | — |
| 1976 | 80° | 64° | 72° | — | — |
| 1975 | 104° | 61° | 82° | — | — |
| 1974 | 104° | 62° | 83° | — | — |
| 1973 | 85° | 54° | 69° | — | — |
| 1972 | 100° | 55° | 78° | — | — |
| 1971 | 83° | 62° | 72° | — | — |
47 years of data from NORTON AFB