Weather on May 18
Rialto, CA
55 Years of Data
Avg High
80°F
Avg Low
53°F
Warmest
2008
84°F avg
Coldest
2011
49°F avg
About This Date
May 18th in Rialto, CA typically brings warm spring weather, with average highs around 80°F and lows near 53°F — a 27°F daily swing. Over 48 years of records, the warmest May 18th was in 2008 (84°F average), while the coldest was 2011 (49°F) — a 35°F range across recorded history. Rain or other precipitation has occurred on about 2% of May 18th dates historically, with the wettest May 18th recording 0.61" of rain.
Planning for May 18th in Rialto, 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 |
|---|---|---|---|---|---|
| 2025 | 73° | 55° | 64° | — | — |
| 2017 | 79° | 48° | 63° | — | — |
| 2016 | 84° | 54° | 69° | — | — |
| 2015 | 63° | 53° | 58° | — | — |
| 2014 | 78° | 57° | 68° | — | — |
| 2013 | 73° | 55° | 64° | — | — |
| 2012 | 71° | 54° | 62° | — | — |
| 2011coldest | 54° | 45° | 49° | — | — |
| 2010 | 62° | 49° | 55° | — | — |
| 2009 | 91° | 64° | 78° | — | — |
| 2008warmest | 98° | 70° | 84° | — | — |
| 2007 | 82° | 51° | 67° | — | — |
| 2006 | 87° | 57° | 72° | — | — |
| 2005 | 81° | 50° | 65° | — | — |
| 2004 | 74° | 54° | 64° | — | — |
| 2003 | 77° | 51° | 64° | — | — |
| 2002 | 78° | 49° | 63° | — | — |
| 2001 | 79° | 53° | 66° | — | — |
| 2000 | 91° | 54° | 72° | — | — |
| 1999 | 85° | 55° | 70° | — | — |
| 1998 | 81° | 49° | 65° | — | — |
| 1997 | 84° | 59° | 72° | — | — |
| 1996 | 80° | 55° | 68° | — | — |
| 1995 | 79° | 48° | 63° | — | — |
| 1994 | 62° | 48° | 55° | 0.61" | — |
| 1993 | 79° | 55° | 67° | — | — |
| 1992 | 87° | 55° | 71° | — | — |
| 1991 | 64° | 44° | 54° | — | — |
| 1990 | 75° | 54° | 64° | — | — |
| 1989 | 74° | 56° | 65° | — | — |
| 1988 | 82° | 51° | 67° | — | — |
| 1987 | 78° | 59° | 69° | — | — |
| 1986 | 96° | 57° | 77° | — | — |
| 1985 | 80° | 49° | 64° | — | — |
| 1984 | 92° | 55° | 73° | — | — |
| 1983 | 90° | 52° | 71° | — | — |
| 1982 | 79° | 55° | 67° | — | — |
| 1981 | 86° | 45° | 65° | — | — |
| 1980 | 91° | 55° | 73° | — | — |
| 1979 | 83° | 54° | 68° | — | — |
| 1978 | 94° | 52° | 73° | — | — |
| 1977 | 76° | 41° | 58° | — | — |
| 1976 | 89° | 54° | 71° | — | — |
| 1975 | 79° | 53° | 66° | — | — |
| 1974 | 68° | 51° | 60° | — | — |
| 1973 | 88° | 55° | 71° | — | — |
| 1972 | 73° | 53° | 63° | — | — |
| 1971 | 89° | 50° | 70° | — | — |
48 years of data from DEVORE CALIFORNIA