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Rialto, CA Weather on April 20
April 20th in Rialto, CA typically brings pleasant spring weather, with average highs around 75°F and lows near 49°F — a 26°F daily swing. Over 48 years of records, the warmest April 20th was in 2009 (82°F average), while the coldest was 1995 (44°F) — a 38°F range across recorded history. Rain or other precipitation has occurred on about 6% of April 20th dates historically, with the wettest April 20th recording 2.54" of rain.
What to Expect on April 20
Planning for April 20th in Rialto, CA? Great weather for outdoor activities.
April 20 Weather Records for Rialto
- •The all-time record high for April 20th in Rialto, CA is 94°F, set in 2009.
- •The coldest April 20th on record dropped to 37°F in 1972.
- •Temperatures have reached 90°F or higher on April 20th in 4 of the last 48 years.
- •Last year (1971), April 20th was 17°F cooler than the long-term average.
Frequently Asked Questions
What was the warmest April 20 ever in Rialto?
The warmest April 20 in Rialto, CA reached 94°F in 2009. That is 19°F above the long-term average high of 75°F.
What was the coldest April 20 ever in Rialto?
The coldest April 20 in Rialto, CA dropped to 37°F in 1972. That is 12°F below the long-term average low of 49°F.
What is the average temperature on April 20 in Rialto?
On April 20, Rialto averages a high of 75°F and a low of 49°F based on 48 years of NOAA weather observations from DEVORE CALIFORNIA.
How many years of weather data are available for April 20 in Rialto?
We have 48 years of weather records for April 20 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.
April 20 Weather History in Rialto
| Year | High | Low | Precip | Snow |
|---|---|---|---|---|
| 2025 | 82°F | 46°F | -- | -- |
| 2017 | 78°F | 54°F | -- | -- |
| 2016 | 84°F | 56°F | -- | -- |
| 2015 | 73°F | 51°F | -- | -- |
| 2014 | 81°F | 52°F | -- | -- |
| 2013 | 89°F | 54°F | -- | -- |
| 2012 | 93°F | 66°F | -- | -- |
| 2011 | 61°F | 52°F | -- | -- |
| 2010 | 65°F | 44°F | -- | -- |
| 2009 | 94°F | 70°F | -- | -- |
| 2008 | 62°F | 46°F | -- | -- |
| 2007 | 46°F | 43°F | -- | -- |
| 2006 | 78°F | 50°F | -- | -- |
| 2005 | 70°F | 43°F | -- | -- |
| 2004 | 73°F | 43°F | -- | -- |
| 2003 | 76°F | 52°F | -- | -- |
| 2002 | 68°F | 38°F | -- | -- |
| 2001 | 57°F | 43°F | -- | -- |
| 2000 | 83°F | 52°F | -- | -- |
| 1999 | 82°F | 53°F | -- | -- |
| 1998 | 90°F | 55°F | -- | -- |
| 1997 | 87°F | 51°F | -- | -- |
| 1996 | 70°F | 47°F | -- | -- |
| 1995 | 49°F | 40°F | -- | -- |
| 1994 | 85°F | 56°F | 0" | -- |
| 1993 | 85°F | 58°F | -- | -- |
| 1992 | 80°F | 53°F | -- | -- |
| 1991 | 62°F | 45°F | -- | -- |
| 1990 | 74°F | 55°F | 0" | -- |
| 1989 | 87°F | 54°F | 0" | -- |
| 1988 | 55°F | 48°F | 2.54" | -- |
| 1987 | 84°F | 50°F | 0" | -- |
| 1986 | 91°F | 47°F | 0" | -- |
| 1985 | 62°F | 51°F | 0" | -- |
| 1984 | 74°F | 48°F | 0" | -- |
| 1983 | 65°F | 51°F | 2.08" | -- |
| 1982 | 84°F | 53°F | 0" | -- |
| 1981 | 65°F | 49°F | 0.18" | -- |
| 1980 | 84°F | 52°F | 0" | -- |
| 1979 | 83°F | 45°F | 0" | -- |
| 1978 | 70°F | 48°F | 0" | -- |
| 1977 | 85°F | 44°F | 0" | -- |
| 1976 | 88°F | 48°F | 0" | -- |
| 1975 | 82°F | 43°F | 0" | -- |
| 1974 | 70°F | 44°F | 0" | -- |
| 1973 | 72°F | 42°F | 0" | -- |
| 1972 | 74°F | 37°F | 0" | -- |
| 1971 | 58°F | 47°F | 0" | -- |
Based on 48 years of data from NOAA station: DEVORE CALIFORNIA
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.