West Covina, CA 91791 Frost Dates
91791, near West Covina, CA: the frost window
The last spring frost here typically falls around 01/08, about 133 days from today. Fall's first freeze usually shows up around 12/28, roughly 354 days after the last spring frost.
West Covina sits in USDA Zone 10a (30 to 35°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
West Covina's growing season runs out in roughly 17 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 West Covina's last frost
01/08 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 02/18 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 12/14 and only about 1 year in 10 sees frost after that.
West Covina against the rest of the dataset
West Covina's growing season runs about 354 days, ranking 2,167 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 971 of 2,555.
Learn more
Two guides worth reading on 91791: the frost range, on how to read the range around West Covina's dates instead of trusting one, and local microclimates, on what one yard in West Covina can differ from the 91791 normal.