Weather on May 21
Rialto, CA
55 Years of Data
Avg High
79°F
Avg Low
54°F
Warmest
2000
85°F avg
Coldest
1991
54°F avg
About This Date
May 21st in Rialto, CA typically brings pleasant spring weather, with average highs around 79°F and lows near 54°F — a 25°F daily swing. Over 48 years of records, the warmest May 21st was in 2000 (85°F average), while the coldest was 1991 (54°F) — a 31°F range across recorded history. Rain or other precipitation has occurred on about 4% of May 21st dates historically.
Planning for May 21st in Rialto, CA? Great weather for outdoor activities.
Warming Trend
0.4°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 95° | 60° | 77° | — | — |
| 2017 | 91° | 66° | 79° | — | — |
| 2016 | 64° | 50° | 57° | — | — |
| 2015 | 62° | 52° | 57° | — | — |
| 2014 | 67° | 48° | 57° | — | — |
| 2013 | 83° | 58° | 70° | — | — |
| 2012 | 92° | 65° | 78° | — | — |
| 2011 | 76° | 50° | 63° | — | — |
| 2010 | 72° | 52° | 62° | — | — |
| 2009 | 80° | 57° | 69° | — | — |
| 2008 | 71° | 54° | 62° | — | — |
| 2007 | 60° | 54° | 57° | — | — |
| 2006 | 71° | 54° | 62° | — | — |
| 2005 | 96° | 62° | 79° | — | — |
| 2004 | 63° | 53° | 58° | — | — |
| 2003 | 99° | 68° | 83° | — | — |
| 2002 | 66° | 45° | 55° | — | — |
| 2001 | 87° | 55° | 71° | — | — |
| 2000warmest | 104° | 67° | 85° | — | — |
| 1999 | 68° | 51° | 60° | — | — |
| 1998 | 71° | 48° | 60° | — | — |
| 1997 | 82° | 58° | 70° | — | — |
| 1996 | 72° | 52° | 62° | — | — |
| 1995 | 70° | 47° | 58° | — | — |
| 1994 | 86° | 47° | 66° | — | — |
| 1993 | 70° | 55° | 62° | — | — |
| 1992 | 74° | 51° | 62° | — | — |
| 1991coldest | 63° | 46° | 54° | — | — |
| 1990 | 78° | 51° | 65° | — | — |
| 1989 | 86° | 54° | 70° | — | — |
| 1988 | 97° | 58° | 77° | — | — |
| 1987 | 86° | 59° | 73° | — | — |
| 1986 | 75° | 57° | 66° | — | — |
| 1985 | 85° | 56° | 70° | — | — |
| 1984 | 86° | 57° | 72° | — | — |
| 1983 | 90° | 54° | 72° | — | — |
| 1982 | 77° | 59° | 68° | — | — |
| 1981 | 80° | 46° | 63° | — | — |
| 1980 | 70° | 55° | 62° | — | — |
| 1979 | 75° | 58° | 66° | — | — |
| 1978 | 84° | 52° | 68° | — | — |
| 1977 | 88° | 53° | 70° | — | — |
| 1976 | 79° | 53° | 66° | — | — |
| 1975 | 70° | 43° | 56° | 0.08" | — |
| 1974 | 89° | 48° | 69° | — | — |
| 1973 | 79° | 56° | 67° | — | — |
| 1972 | 72° | 42° | 57° | 0.08" | — |
| 1971 | 76° | 48° | 62° | — | — |
48 years of data from DEVORE CALIFORNIA