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Rialto, CA Weather on August 25
August 25th in Rialto, CA typically brings hot summer weather, with average highs around 94°F and lows near 65°F — a 29°F daily swing. Over 47 years of records, the warmest August 25th was in 2010 (91°F average), while the coldest was 1983 (67°F) — a 24°F range across recorded history. This date has historically been dry, with little recorded precipitation.
What to Expect on August 25
Planning for August 25th in Rialto, CA? Stay hydrated and seek shade during peak afternoon hours.
August 25 Weather Records for Rialto
- •The all-time record high for August 25th in Rialto, CA is 110°F, set in 1985.
- •The coldest August 25th on record dropped to 56°F in 1975.
- •Temperatures have reached 90°F or higher on August 25th in 32 of the last 47 years.
- •Last year (1971), August 25th was 6°F warmer than the long-term average.
Frequently Asked Questions
What was the warmest August 25 ever in Rialto?
The warmest August 25 in Rialto, CA reached 110°F in 1985. That is 16°F above the long-term average high of 94°F.
What was the coldest August 25 ever in Rialto?
The coldest August 25 in Rialto, CA dropped to 56°F in 1975. That is 9°F below the long-term average low of 65°F.
What is the average temperature on August 25 in Rialto?
On August 25, Rialto averages a high of 94°F and a low of 65°F based on 47 years of NOAA weather observations from FONTANA 5 N.
How many years of weather data are available for August 25 in Rialto?
We have 47 years of weather records for August 25 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 25 Weather History in Rialto
| Year | High | Low | Precip | Snow |
|---|---|---|---|---|
| 2025 | 100°F | 73°F | -- | -- |
| 2017 | 90°F | 63°F | -- | -- |
| 2016 | 89°F | 63°F | -- | -- |
| 2015 | 87°F | 74°F | -- | -- |
| 2014 | 81°F | 63°F | -- | -- |
| 2013 | 94°F | 71°F | -- | -- |
| 2012 | 84°F | 61°F | -- | -- |
| 2011 | 100°F | 73°F | -- | -- |
| 2010 | 104°F | 77°F | -- | -- |
| 2009 | 95°F | 64°F | -- | -- |
| 2008 | 101°F | 73°F | -- | -- |
| 2007 | 92°F | 63°F | -- | -- |
| 2006 | 89°F | 63°F | -- | -- |
| 2005 | 98°F | 69°F | -- | -- |
| 2004 | 88°F | 59°F | -- | -- |
| 2003 | 99°F | 69°F | -- | -- |
| 2002 | 95°F | 65°F | -- | -- |
| 2001 | 104°F | 66°F | -- | -- |
| 2000 | 94°F | 70°F | -- | -- |
| 1999 | 106°F | 74°F | -- | -- |
| 1998 | 95°F | 67°F | -- | -- |
| 1997 | 96°F | 65°F | -- | -- |
| 1996 | 103°F | 72°F | -- | -- |
| 1995 | 95°F | 65°F | -- | -- |
| 1994 | 99°F | 59°F | 0" | -- |
| 1993 | 96°F | 68°F | -- | -- |
| 1992 | 88°F | 58°F | -- | -- |
| 1991 | 89°F | 64°F | -- | -- |
| 1990 | 82°F | 62°F | 0" | -- |
| 1989 | 80°F | 58°F | 0" | -- |
| 1988 | 97°F | 72°F | 0" | -- |
| 1987 | 85°F | 57°F | 0" | -- |
| 1985 | 110°F | 70°F | 0" | -- |
| 1984 | 93°F | 64°F | 0" | -- |
| 1983 | 74°F | 61°F | 0" | -- |
| 1982 | 94°F | 66°F | 0" | -- |
| 1981 | 109°F | 70°F | 0" | -- |
| 1980 | 94°F | 63°F | 0" | -- |
| 1979 | 98°F | 64°F | 0" | -- |
| 1978 | 84°F | 67°F | 0" | -- |
| 1977 | 90°F | 61°F | 0" | -- |
| 1976 | 98°F | 62°F | 0" | -- |
| 1975 | 99°F | 56°F | 0" | -- |
| 1974 | 101°F | 60°F | 0" | -- |
| 1973 | 82°F | 57°F | 0" | -- |
| 1972 | 85°F | 63°F | 0" | -- |
| 1971 | 100°F | 60°F | 0" | -- |
Based on 47 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.