El Cajon, CA 91916 Frost Dates
91916, near El Cajon, CA: the frost window
Typically, the last spring freeze lands around 04/19, roughly 234 days out. Fall's first freeze usually shows up around 10/27, roughly 190 days after the last spring frost.
El Cajon sits in USDA Zone 9b (25 to 30°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
Stretching the season past the first frost
El Cajon's growing season runs out in roughly 9 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
The actual range around El Cajon's last frost
04/19 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/24 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/14 and only about 1 year in 10 sees frost after that.
El Cajon against the rest of the dataset
At roughly 190 frost-free days, El Cajon places 20,978 of 40,283 ZIP codes in this dataset. Within CA, it ranks 2,311 of 2,555.
Learn more
Two guides worth reading on 91916: local microclimates, on what one yard in El Cajon can differ from the 91916 normal, and zone vs. frost date, on why Zone 9b and El Cajon's frost date answer different questions.