Weather on March 21
Fontana, CA
55 Years of Data
Avg High
72°F
Avg Low
48°F
Warmest
2026
77°F avg
Coldest
1973
47°F avg
About This Date
March 21st in Fontana, CA typically brings pleasant spring weather, with average highs around 72°F and lows near 48°F. Over 56 years of records, the warmest March 21st was in 2026 (77°F average), while the coldest was 1973 (47°F) — a 30°F range across recorded history. Rain or other precipitation has occurred on about 30% of March 21st dates historically, with the wettest March 21st recording 2.95" of rain. The last decade has been 1.6°F cooler on this date compared to 20-30 years ago.
The last decade has been 1.6°F cooler on this date compared to 20-30 years ago.
Planning for March 21st in Fontana, CA? Great weather for outdoor activities. Consider bringing rain gear or an umbrella.
Warming Trend
0.8°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2026warmest | 91° | 63° | 77° | — | — |
| 2025 | 79° | 48° | 63° | — | — |
| 2024 | 73° | 51° | 62° | — | — |
| 2023 | 59° | 45° | 52° | 2.72" | — |
| 2022 | 82° | 47° | 64° | — | — |
| 2021 | 68° | 43° | 55° | — | — |
| 2020 | 66° | 48° | 57° | — | — |
| 2019 | 62° | 52° | 57° | 0.03" | — |
| 2018 | 68° | 54° | 61° | 0.28" | — |
| 2017 | 65° | 53° | 59° | 0.36" | — |
| 2016 | 73° | 51° | 62° | — | — |
| 2015 | 79° | 54° | 66° | — | — |
| 2014 | 70° | 54° | 62° | — | — |
| 2013 | 74° | 51° | 62° | — | — |
| 2012 | 78° | 47° | 62° | — | — |
| 2011 | 55° | 44° | 50° | 2.95" | — |
| 2010 | 80° | 51° | 66° | — | — |
| 2009 | 64° | 52° | 58° | — | — |
| 2008 | 83° | 48° | 65° | — | — |
| 2007 | 64° | 50° | 57° | 0.23" | — |
| 2006 | 58° | 42° | 50° | 0.33" | — |
| 2005 | 68° | 50° | 59° | — | — |
| 2004 | 81° | 51° | 66° | — | — |
| 2003 | 75° | 46° | 61° | — | — |
| 2002 | 84° | 48° | 66° | — | — |
| 2001 | 75° | 52° | 63° | — | — |
| 2000 | 71° | 47° | 59° | — | — |
| 1999 | 66° | 42° | 54° | — | — |
| 1998 | 71° | 51° | 61° | — | — |
| 1997 | 90° | 48° | 69° | — | — |
| 1996 | 78° | 53° | 66° | — | — |
| 1995 | 65° | 50° | 57° | 0.91" | — |
| 1994 | 74° | 49° | 61° | 0.51" | — |
| 1993 | 75° | 49° | 62° | — | — |
| 1992 | 64° | 51° | 58° | 2.82" | — |
| 1991 | 58° | 42° | 50° | 0.61" | — |
| 1990 | 90° | 51° | 70° | — | — |
| 1989 | 86° | 44° | 65° | — | — |
| 1988 | 84° | 47° | 65° | — | — |
| 1987 | 69° | 39° | 54° | 1.27" | — |
| 1986 | 87° | 45° | 66° | — | — |
| 1985 | 69° | 41° | 55° | — | — |
| 1984 | 78° | 42° | 60° | — | — |
| 1983 | 60° | 46° | 53° | 0.86" | — |
| 1982 | 67° | 35° | 51° | — | — |
| 1981 | 64° | 44° | 54° | — | — |
| 1980 | 68° | 45° | 56° | 0.08" | — |
| 1979 | 56° | 44° | 50° | 0.23" | — |
| 1978 | 67° | 47° | 57° | 0.41" | — |
| 1977 | 87° | 45° | 66° | — | — |
| 1976 | 77° | 51° | 64° | — | — |
| 1975 | 64° | 49° | 56° | — | — |
| 1974 | 69° | 52° | 60° | — | — |
| 1973coldest | 54° | 41° | 47° | 0.05" | — |
| 1972 | 84° | 46° | 65° | — | — |
| 1971 | 73° | 46° | 60° | — | — |
56 years of data from FONTANA KAISER