Weather on September 18
San Bernardino, CA
55 Years of Data
Avg High
89°F
Avg Low
60°F
Warmest
1984
89°F avg
Coldest
1985
63°F avg
About This Date
September 18th in San Bernardino, CA typically brings warm fall weather, with average highs around 89°F and lows near 60°F — a 29°F daily swing. Over 48 years of records, the warmest September 18th was in 1984 (89°F average), while the coldest was 1985 (63°F) — a 26°F range across recorded history. Rain or other precipitation has occurred on about 4% of September 18th dates historically.
Planning for September 18th in San Bernardino, CA? Stay hydrated and seek shade during peak afternoon hours.
Warming Trend
0.7°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 88° | 69° | 78° | — | — |
| 2017 | 79° | 57° | 68° | — | — |
| 2016 | 101° | 75° | 88° | — | — |
| 2015 | 92° | 66° | 79° | — | — |
| 2014 | 86° | 66° | 76° | — | — |
| 2013 | 82° | 56° | 69° | — | — |
| 2012 | 95° | 61° | 78° | — | — |
| 2011 | 99° | 55° | 77° | — | — |
| 2010 | 92° | 52° | 72° | — | — |
| 2009 | 102° | 63° | 82° | — | — |
| 2008 | 94° | 65° | 79° | — | — |
| 2007 | 84° | 54° | 69° | — | — |
| 2006 | 99° | 55° | 77° | — | — |
| 2005 | 89° | 51° | 70° | — | — |
| 2004 | 89° | 57° | 73° | — | — |
| 2003 | 96° | 57° | 77° | — | — |
| 2002 | 86° | 60° | 73° | — | — |
| 2001 | 89° | 78° | 84° | — | — |
| 2000 | 100° | 68° | 84° | — | — |
| 1999 | 71° | 58° | 64° | — | — |
| 1998 | 90° | 55° | 72° | — | — |
| 1997 | 90° | 63° | 76° | — | — |
| 1996 | 84° | 58° | 71° | — | — |
| 1995 | 92° | 59° | 75° | — | — |
| 1994 | 91° | 58° | 74° | — | — |
| 1993 | 79° | 54° | 66° | — | — |
| 1992 | 95° | 58° | 76° | — | — |
| 1991 | 93° | 58° | 75° | — | — |
| 1990 | 77° | 63° | 70° | — | — |
| 1989 | 72° | 56° | 64° | — | — |
| 1988 | 78° | 58° | 68° | — | — |
| 1987 | 89° | 56° | 72° | — | — |
| 1986 | 80° | 56° | 68° | — | — |
| 1985coldest | 77° | 49° | 63° | 0.03" | — |
| 1984warmest | 107° | 71° | 89° | 0.28" | — |
| 1983 | 98° | 67° | 82° | — | — |
| 1982 | 89° | 60° | 75° | — | — |
| 1981 | 96° | 67° | 81° | — | — |
| 1980 | 97° | 63° | 80° | — | — |
| 1979 | 105° | 64° | 85° | — | — |
| 1978 | 79° | 54° | 66° | — | — |
| 1977 | 86° | 51° | 69° | — | — |
| 1976 | 82° | 54° | 68° | — | — |
| 1975 | 94° | 66° | 80° | — | — |
| 1974 | 94° | 57° | 75° | — | — |
| 1973 | 85° | 50° | 67° | — | — |
| 1972 | 83° | 57° | 70° | — | — |
| 1971 | 95° | 61° | 78° | — | — |
48 years of data from NORTON AFB