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Rialto, CA Weather on August 12
August 12th in Rialto, CA typically brings hot summer weather, with average highs around 95°F and lows near 65°F — a 30°F daily swing. Over 48 years of records, the warmest August 12th was in 1996 (89°F average), while the coldest was 2011 (70°F) — a 19°F range across recorded history. Rain or other precipitation has occurred on about 2% of August 12th dates historically.
What to Expect on August 12
Planning for August 12th in Rialto, CA? Stay hydrated and seek shade during peak afternoon hours.
August 12 Weather Records for Rialto
- •The all-time record high for August 12th in Rialto, CA is 109°F, set in 1996.
- •The coldest August 12th on record dropped to 53°F in 2011.
- •Temperatures have reached 90°F or higher on August 12th in 35 of the last 48 years.
Frequently Asked Questions
What was the warmest August 12 ever in Rialto?
The warmest August 12 in Rialto, CA reached 109°F in 1996. That is 14°F above the long-term average high of 95°F.
What was the coldest August 12 ever in Rialto?
The coldest August 12 in Rialto, CA dropped to 53°F in 2011. That is 12°F below the long-term average low of 65°F.
What is the average temperature on August 12 in Rialto?
On August 12, Rialto averages a high of 95°F and a low of 65°F based on 48 years of NOAA weather observations from FONTANA 5 N.
How many years of weather data are available for August 12 in Rialto?
We have 48 years of weather records for August 12 in Rialto, CA, sourced from NOAA's Global Historical Climatology Network. Records include daily high and low temperatures, precipitation, and snowfall data going back to 2025.
August 12 Weather History in Rialto
| Year | High | Low | Precip | Snow |
|---|---|---|---|---|
| 2025 | 99°F | 66°F | -- | -- |
| 2017 | 95°F | 68°F | -- | -- |
| 2016 | 92°F | 64°F | -- | -- |
| 2015 | 98°F | 62°F | -- | -- |
| 2014 | 92°F | 67°F | -- | -- |
| 2013 | 89°F | 59°F | -- | -- |
| 2012 | 103°F | 76°F | -- | -- |
| 2011 | 88°F | 53°F | -- | -- |
| 2010 | 87°F | 57°F | -- | -- |
| 2009 | 93°F | 66°F | -- | -- |
| 2008 | 93°F | 65°F | -- | -- |
| 2007 | 97°F | 65°F | -- | -- |
| 2006 | 88°F | 59°F | -- | -- |
| 2005 | 90°F | 60°F | -- | -- |
| 2004 | 96°F | 71°F | -- | -- |
| 2003 | 103°F | 70°F | -- | -- |
| 2002 | 83°F | 67°F | -- | -- |
| 2001 | 96°F | 62°F | -- | -- |
| 2000 | 102°F | 70°F | -- | -- |
| 1999 | 93°F | 56°F | -- | -- |
| 1998 | 103°F | 70°F | -- | -- |
| 1997 | 89°F | 54°F | -- | -- |
| 1996 | 109°F | 69°F | -- | -- |
| 1995 | 99°F | 69°F | -- | -- |
| 1994 | 106°F | 70°F | 0" | -- |
| 1993 | 86°F | 57°F | -- | -- |
| 1992 | 101°F | 72°F | -- | -- |
| 1991 | 90°F | 69°F | -- | -- |
| 1990 | 98°F | 73°F | 0" | -- |
| 1989 | 94°F | 68°F | 0" | -- |
| 1988 | 85°F | 59°F | 0" | -- |
| 1987 | 89°F | 64°F | 0" | -- |
| 1986 | 96°F | 66°F | 0" | -- |
| 1985 | 85°F | 60°F | 0" | -- |
| 1984 | 98°F | 68°F | 0" | -- |
| 1983 | 101°F | 67°F | 0" | -- |
| 1982 | 91°F | 62°F | 0" | -- |
| 1981 | 99°F | 64°F | 0" | -- |
| 1980 | 105°F | 71°F | 0" | -- |
| 1979 | 83°F | 64°F | 0" | -- |
| 1978 | 86°F | 73°F | 0" | -- |
| 1977 | 101°F | 65°F | 0" | -- |
| 1976 | 97°F | 57°F | 0" | -- |
| 1975 | 94°F | 59°F | 0" | -- |
| 1974 | 88°F | 63°F | 0" | -- |
| 1973 | 100°F | 63°F | 0" | -- |
| 1972 | 90°F | 66°F | 0.15" | -- |
| 1971 | 99°F | 66°F | 0" | -- |
Based on 48 years of data from NOAA station: FONTANA 5 N
Monthly Climate Averages
Historical temperature and precipitation averages for Rialto, CA, based on 55+ years of weather data.
Temperatures in Fahrenheit. Precipitation and snowfall in inches.