Weather on August 31
Fontana, CA
55 Years of Data
Avg High
95°F
Avg Low
64°F
Warmest
2017
95°F avg
Coldest
1973
70°F avg
About This Date
August 31st in Fontana, CA typically brings hot summer weather, with average highs around 95°F and lows near 64°F — a 31°F daily swing. Over 54 years of records, the warmest August 31st was in 2017 (95°F average), while the coldest was 1973 (70°F) — a 25°F range across recorded history. Rain or other precipitation has occurred on about 4% of August 31st dates historically. The last decade has been 3.8°F warmer on this date compared to 20-30 years ago.
The last decade has been 3.8°F warmer on this date compared to 20-30 years ago.
Planning for August 31st in Fontana, CA? Stay hydrated and seek shade during peak afternoon hours.
Warming Trend
1.1°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 101° | 70° | 85° | — | — |
| 2024 | 94° | 63° | 78° | — | — |
| 2023 | 94° | 69° | 81° | — | — |
| 2022 | 108° | 72° | 90° | — | — |
| 2021 | 84° | 67° | 75° | — | — |
| 2020 | 90° | 60° | 75° | — | — |
| 2019 | 99° | 68° | 83° | — | — |
| 2018 | 92° | 63° | 77° | — | — |
| 2017warmest | 112° | 78° | 95° | 0.05" | — |
| 2016 | 101° | 69° | 85° | — | — |
| 2015 | 91° | 66° | 79° | — | — |
| 2014 | 95° | 68° | 82° | — | — |
| 2013 | 96° | 77° | 87° | — | — |
| 2012 | 96° | 70° | 83° | — | — |
| 2011 | 91° | 59° | 75° | — | — |
| 2010 | 89° | 60° | 75° | — | — |
| 2009 | 101° | 71° | 86° | — | — |
| 2008 | 90° | 67° | 78° | — | — |
| 2007 | 108° | 78° | 93° | — | — |
| 2006 | 97° | 65° | 81° | — | — |
| 2005 | 91° | 60° | 76° | — | — |
| 2004 | 101° | 64° | 82° | — | — |
| 2003 | 94° | 63° | 78° | — | — |
| 2002 | 98° | 64° | 81° | — | — |
| 2001 | 89° | 60° | 75° | — | — |
| 2000 | 78° | 62° | 70° | — | — |
| 1999 | 88° | 56° | 72° | — | — |
| 1998 | 105° | 74° | 89° | 0.33" | — |
| 1997 | 99° | 62° | 80° | — | — |
| 1996 | 101° | 66° | 83° | — | — |
| 1995 | 106° | 65° | 85° | — | — |
| 1994 | 87° | 61° | 74° | — | — |
| 1993 | 91° | 62° | 77° | — | — |
| 1991 | 94° | 60° | 77° | — | — |
| 1990 | 94° | 63° | 78° | — | — |
| 1989 | 92° | 57° | 74° | — | — |
| 1988 | 100° | 68° | 84° | — | — |
| 1987 | 99° | 63° | 81° | — | — |
| 1986 | 97° | 55° | 76° | — | — |
| 1985 | 105° | 66° | 86° | — | — |
| 1984 | 98° | 65° | 81° | — | — |
| 1983 | 96° | 61° | 78° | — | — |
| 1982 | 97° | 59° | 78° | — | — |
| 1981 | 93° | 59° | 76° | — | — |
| 1980 | 86° | 53° | 70° | — | — |
| 1979 | 89° | 53° | 71° | — | — |
| 1978 | 97° | 56° | 76° | — | — |
| 1977 | 88° | 65° | 76° | — | — |
| 1976 | 100° | 67° | 83° | — | — |
| 1975 | 93° | 61° | 77° | — | — |
| 1974 | 96° | 63° | 79° | — | — |
| 1973coldest | 82° | 57° | 70° | — | — |
| 1972 | 99° | 71° | 85° | — | — |
| 1971 | 93° | 62° | 78° | — | — |
54 years of data from FONTANA KAISER