NPS Photo / Public domain
Fullerton, CA Weather on April 20
April 20th in Fullerton, CA typically brings pleasant spring weather, with average highs around 76°F and lows near 52°F. Over 55 years of records, the warmest April 20th was in 2009 (84°F average), while the coldest was 1971 (52°F) — a 32°F range across recorded history. Rain or other precipitation has occurred on about 5% of April 20th dates historically, with the wettest April 20th recording 2.29" of rain. The last decade has been 2.4°F warmer on this date compared to 20-30 years ago.
What to Expect on April 20
Planning for April 20th in Fullerton, CA? Great weather for outdoor activities.
April 20 Weather Records for Fullerton
- •The all-time record high for April 20th in Fullerton, CA is 104°F, set in 2009.
- •The coldest April 20th on record dropped to 38°F in 1972.
- •Temperatures have reached 90°F or higher on April 20th in 4 of the last 55 years.
- •Last year (1971), April 20th was 15°F cooler than the long-term average.
Frequently Asked Questions
What was the warmest April 20 ever in Fullerton?
The warmest April 20 in Fullerton, CA reached 104°F in 2009. That is 28°F above the long-term average high of 76°F.
What was the coldest April 20 ever in Fullerton?
The coldest April 20 in Fullerton, CA dropped to 38°F in 1972. That is 14°F below the long-term average low of 52°F.
What is the average temperature on April 20 in Fullerton?
On April 20, Fullerton averages a high of 76°F and a low of 52°F based on 55 years of NOAA weather observations from ANAHEIM.
How many years of weather data are available for April 20 in Fullerton?
We have 55 years of weather records for April 20 in Fullerton, 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 Fullerton
| Year | High | Low | Precip | Snow |
|---|---|---|---|---|
| 2025 | 76°F | 50°F | 0" | -- |
| 2024 | 73°F | 58°F | 0" | -- |
| 2023 | 83°F | 50°F | 0" | -- |
| 2022 | 74°F | 58°F | 0" | -- |
| 2021 | 71°F | 57°F | 0" | -- |
| 2020 | 71°F | 57°F | 0" | -- |
| 2019 | 72°F | 57°F | 0" | -- |
| 2018 | 77°F | 51°F | 0" | -- |
| 2017 | 79°F | 56°F | 0" | -- |
| 2016 | 90°F | 58°F | 0" | -- |
| 2015 | 75°F | 58°F | 0" | -- |
| 2014 | 79°F | 56°F | 0" | -- |
| 2013 | 85°F | 53°F | 0" | -- |
| 2012 | 85°F | 56°F | 0" | -- |
| 2011 | 69°F | 58°F | 0" | -- |
| 2010 | 74°F | 55°F | 0" | -- |
| 2009 | 104°F | 65°F | 0" | -- |
| 2008 | 68°F | 52°F | 0" | -- |
| 2007 | 72°F | 52°F | 0.86" | -- |
| 2006 | 82°F | 52°F | 0" | -- |
| 2005 | 73°F | 49°F | 0" | -- |
| 2004 | 72°F | 52°F | 0" | -- |
| 2003 | 81°F | 53°F | 0" | -- |
| 2002 | 69°F | 47°F | 0" | -- |
| 2001 | 67°F | 52°F | 0" | -- |
| 2000 | 80°F | 49°F | 0" | -- |
| 1999 | 85°F | 55°F | 0" | -- |
| 1998 | 86°F | 49°F | 0" | -- |
| 1997 | 75°F | 58°F | 0" | -- |
| 1996 | 70°F | 49°F | 0" | -- |
| 1995 | 62°F | 48°F | 0" | -- |
| 1994 | 75°F | 56°F | 0" | -- |
| 1993 | 85°F | 58°F | 0" | -- |
| 1992 | 84°F | 60°F | 0" | -- |
| 1991 | 66°F | 54°F | 0" | -- |
| 1990 | 72°F | 59°F | 0" | -- |
| 1989 | 76°F | 60°F | 0" | -- |
| 1988 | 65°F | 51°F | 2.29" | -- |
| 1987 | 90°F | 49°F | 0" | -- |
| 1986 | 91°F | 55°F | 0" | -- |
| 1985 | 66°F | 51°F | 0" | -- |
| 1984 | 74°F | 51°F | 0" | -- |
| 1983 | 66°F | 51°F | 1.57" | -- |
| 1982 | 88°F | 43°F | 0" | -- |
| 1981 | 71°F | 44°F | 0" | -- |
| 1980 | 74°F | 50°F | 0" | -- |
| 1979 | 79°F | 43°F | 0" | -- |
| 1978 | 70°F | 48°F | 0" | -- |
| 1977 | 79°F | 43°F | 0" | -- |
| 1976 | 86°F | 50°F | 0" | -- |
| 1975 | 75°F | 43°F | 0" | -- |
| 1974 | 69°F | 42°F | 0" | -- |
| 1973 | 74°F | 39°F | 0" | -- |
| 1972 | 71°F | 38°F | 0" | -- |
| 1971 | 61°F | 44°F | 0" | -- |
Based on 55 years of data from NOAA station: ANAHEIM
Monthly Climate Averages
Historical temperature and precipitation averages for Fullerton, CA, based on 55+ years of weather data.
Temperatures in Fahrenheit. Precipitation and snowfall in inches.