Weather on August 9
Rialto, CA
55 Years of Data
Avg High
96°F
Avg Low
65°F
Warmest
2012
91°F avg
Coldest
2010
70°F avg
About This Date
August 9th in Rialto, CA typically brings hot summer weather, with average highs around 96°F and lows near 65°F — a 31°F daily swing. Over 48 years of records, the warmest August 9th was in 2012 (91°F average), while the coldest was 2010 (70°F) — a 21°F range across recorded history. Rain or other precipitation has occurred on about 2% of August 9th dates historically.
Planning for August 9th in Rialto, CA? Stay hydrated and seek shade during peak afternoon hours.
Cooling Trend
0.9°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 100° | 68° | 84° | — | — |
| 2017 | 92° | 69° | 80° | — | — |
| 2016 | 87° | 59° | 73° | — | — |
| 2015 | 83° | 57° | 70° | — | — |
| 2014 | 92° | 61° | 76° | — | — |
| 2013 | 84° | 56° | 70° | — | — |
| 2012warmest | 104° | 78° | 91° | — | — |
| 2011 | 87° | 60° | 74° | — | — |
| 2010coldest | 85° | 56° | 70° | — | — |
| 2009 | 87° | 60° | 74° | — | — |
| 2008 | 89° | 65° | 77° | — | — |
| 2007 | 90° | 61° | 75° | — | — |
| 2006 | 101° | 67° | 84° | — | — |
| 2005 | 94° | 67° | 80° | — | — |
| 2004 | 104° | 70° | 87° | — | — |
| 2003 | 102° | 69° | 86° | — | — |
| 2002 | 105° | 70° | 87° | — | — |
| 2001 | 96° | 65° | 80° | — | — |
| 2000 | 97° | 66° | 81° | — | — |
| 1999 | 88° | 55° | 71° | — | — |
| 1998 | 101° | 71° | 86° | — | — |
| 1997 | 87° | 63° | 75° | — | — |
| 1996 | 107° | 65° | 86° | — | — |
| 1995 | 102° | 69° | 86° | — | — |
| 1994 | 101° | 70° | 85° | — | — |
| 1993 | 93° | 66° | 80° | — | — |
| 1992 | 99° | 65° | 82° | — | — |
| 1991 | 97° | 68° | 82° | — | — |
| 1990 | 95° | 65° | 80° | — | — |
| 1989 | 94° | 66° | 80° | — | — |
| 1988 | 89° | 60° | 75° | — | — |
| 1987 | 95° | 61° | 78° | — | — |
| 1986 | 94° | 65° | 79° | — | — |
| 1985 | 93° | 59° | 76° | — | — |
| 1984 | 95° | 66° | 81° | — | — |
| 1983 | 97° | 72° | 84° | 0.41" | — |
| 1982 | 103° | 66° | 84° | — | — |
| 1981 | 106° | 67° | 86° | — | — |
| 1980 | 108° | 62° | 85° | — | — |
| 1979 | 102° | 67° | 84° | — | — |
| 1978 | 96° | 72° | 84° | — | — |
| 1977 | 97° | 59° | 78° | — | — |
| 1976 | 95° | 57° | 76° | — | — |
| 1975 | 96° | 66° | 81° | — | — |
| 1974 | 86° | 63° | 74° | — | — |
| 1973 | 97° | 60° | 78° | — | — |
| 1972 | 96° | 66° | 81° | — | — |
| 1971 | 109° | 69° | 89° | — | — |
48 years of data from FONTANA 5 N