Weather on October 21
Rialto, CA
55 Years of Data
Avg High
78°F
Avg Low
55°F
Warmest
2003
88°F avg
Coldest
2004
55°F avg
About This Date
October 21st in Rialto, CA typically brings pleasant fall weather, with average highs around 78°F and lows near 55°F. Over 48 years of records, the warmest October 21st was in 2003 (88°F average), while the coldest was 2004 (55°F) — a 33°F range across recorded history. Rain or other precipitation has occurred on about 6% of October 21st dates historically.
Planning for October 21st in Rialto, CA? Great weather for outdoor activities.
Warming Trend
1.0°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 91° | 55° | 73° | — | — |
| 2017 | 77° | 55° | 66° | — | — |
| 2016 | 91° | 65° | 78° | — | — |
| 2015 | 78° | 59° | 69° | — | — |
| 2014 | 78° | 58° | 68° | — | — |
| 2013 | 83° | 56° | 69° | — | — |
| 2012 | 65° | 58° | 61° | — | — |
| 2011 | 78° | 49° | 63° | — | — |
| 2010 | 59° | 55° | 57° | — | — |
| 2009 | 80° | 62° | 71° | — | — |
| 2008 | 89° | 66° | 78° | — | — |
| 2007 | 70° | 57° | 63° | — | — |
| 2006 | 83° | 61° | 72° | — | — |
| 2005 | 88° | 57° | 72° | — | — |
| 2004coldest | 65° | 46° | 55° | — | — |
| 2003warmest | 103° | 73° | 88° | — | — |
| 2002 | 68° | 46° | 57° | — | — |
| 2001 | 78° | 54° | 66° | — | — |
| 2000 | 62° | 54° | 58° | — | — |
| 1999 | 95° | 66° | 81° | — | — |
| 1998 | 85° | 58° | 71° | — | — |
| 1997 | 72° | 58° | 65° | — | — |
| 1996 | 68° | 51° | 60° | — | — |
| 1995 | 77° | 53° | 65° | — | — |
| 1994 | 80° | 47° | 63° | — | — |
| 1993 | 86° | 60° | 73° | — | — |
| 1992 | 64° | 55° | 60° | — | — |
| 1991 | 73° | 55° | 64° | — | — |
| 1990 | 82° | 46° | 64° | — | — |
| 1989 | 68° | 56° | 62° | 0.13" | — |
| 1988 | 81° | 57° | 69° | — | — |
| 1987 | 78° | 55° | 67° | — | — |
| 1986 | 80° | 47° | 63° | — | — |
| 1985 | 68° | 56° | 62° | 0.05" | — |
| 1984 | 75° | 49° | 62° | — | — |
| 1983 | 90° | 53° | 71° | — | — |
| 1982 | 84° | 53° | 69° | — | — |
| 1981 | 84° | 50° | 67° | — | — |
| 1980 | 89° | 51° | 70° | — | — |
| 1979 | 76° | 48° | 62° | — | — |
| 1978 | 79° | 58° | 68° | — | — |
| 1977 | 74° | 56° | 65° | — | — |
| 1976 | 80° | 62° | 71° | 0.13" | — |
| 1975 | 78° | 52° | 65° | — | — |
| 1974 | 72° | 57° | 64° | — | — |
| 1973 | 80° | 47° | 63° | — | — |
| 1972 | 72° | 47° | 59° | — | — |
| 1971 | 87° | 43° | 65° | — | — |
48 years of data from DEVORE CALIFORNIA