Weather on December 17
Rialto, CA
55 Years of Data
Avg High
65°F
Avg Low
45°F
Warmest
1999
73°F avg
Coldest
2008
39°F avg
About This Date
December 17th in Rialto, CA typically brings mild winter weather, with average highs around 65°F and lows near 45°F. Over 47 years of records, the warmest December 17th was in 1999 (73°F average), while the coldest was 2008 (39°F) — a 34°F range across recorded history. Rain or other precipitation has occurred on about 6% of December 17th dates historically, with the wettest December 17th recording 1.57" of rain.
Planning for December 17th in Rialto, CA? Great weather for outdoor activities.
Cooling Trend
0.6°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 77° | 51° | 64° | — | — |
| 2016 | 55° | 36° | 45° | — | — |
| 2015 | 64° | 41° | 53° | — | — |
| 2014 | 53° | 45° | 49° | — | — |
| 2013 | 78° | 64° | 71° | — | — |
| 2012 | 53° | 47° | 50° | — | — |
| 2011 | 58° | 45° | 51° | — | — |
| 2010 | 51° | 45° | 48° | — | — |
| 2009 | 68° | 53° | 61° | — | — |
| 2008coldest | 44° | 33° | 39° | — | — |
| 2007 | 56° | 41° | 48° | — | — |
| 2006 | 48° | 38° | 43° | — | — |
| 2005 | 52° | 44° | 48° | — | — |
| 2004 | 70° | 55° | 62° | — | — |
| 2003 | 65° | 48° | 56° | — | — |
| 2002 | 53° | 39° | 46° | — | — |
| 2001 | 66° | 41° | 54° | — | — |
| 2000 | 78° | 56° | 67° | — | — |
| 1999warmest | 86° | 59° | 73° | — | — |
| 1998 | 82° | 52° | 67° | — | — |
| 1997 | 72° | 46° | 59° | — | — |
| 1996 | 67° | 63° | 65° | — | — |
| 1995 | 64° | 48° | 56° | — | — |
| 1994 | 70° | 53° | 61° | — | — |
| 1993 | 62° | 42° | 52° | — | — |
| 1992 | 52° | 38° | 45° | — | — |
| 1991 | 63° | 52° | 57° | — | — |
| 1990 | 59° | 38° | 48° | — | — |
| 1989 | 66° | 35° | 51° | — | — |
| 1988 | 56° | 42° | 49° | 0.89" | — |
| 1987 | 49° | 40° | 44° | 1.57" | — |
| 1986 | 69° | 42° | 56° | — | — |
| 1985 | 75° | 43° | 59° | — | — |
| 1984 | 60° | 27° | 43° | — | — |
| 1983 | 63° | 53° | 58° | — | — |
| 1982 | 72° | 35° | 53° | — | — |
| 1981 | 78° | 47° | 62° | — | — |
| 1980 | 82° | 51° | 67° | — | — |
| 1979 | 84° | 41° | 63° | — | — |
| 1978 | 57° | 45° | 51° | — | — |
| 1977 | 67° | 43° | 55° | 0.15" | — |
| 1976 | 77° | 38° | 57° | — | — |
| 1975 | 67° | 55° | 61° | — | — |
| 1974 | 76° | 42° | 59° | — | — |
| 1973 | 76° | 41° | 58° | — | — |
| 1972 | 70° | 42° | 56° | — | — |
| 1971 | 67° | 33° | 50° | — | — |
47 years of data from FONTANA 5 N