Pomona, CA 91766 Frost Dates
91766, near Pomona, 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.
Zone 10a (30 to 35°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Pomona, not a forecast for this year.
Stretching the season past the first frost
Pomona'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.
Why 01/08 isn't a guarantee
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.
Pomona against the rest of the dataset
About 354 days separate Pomona's last and first frost, putting it 2,164 of 40,283 ZIP codes nationally. Within CA, it ranks 968 of 2,555.
Learn more
Two guides worth reading on 91766: the frost range, on how to read the range around Pomona's dates instead of trusting one, and local microclimates, on what one yard in Pomona can differ from the 91766 normal.