Fontana, CA 92335 Frost Dates
92335, near Fontana, CA: the frost window
The last spring frost here typically falls around 01/04, about 129 days from today. Fall's first freeze usually shows up around 12/30, roughly 365 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 Fontana, not a forecast for this year.
Stretching the season past the first frost
Fontana's growing season runs out in roughly 18 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 Fontana's last frost
01/04 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 02/07 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.
Fontana against the rest of the dataset
Fontana's growing season runs about 365 days, ranking 348 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 111 of 2,555.
Learn more
Two guides worth reading on 92335: local microclimates, on what one yard in Fontana can differ from the 92335 normal, and zone vs. frost date, on why Zone 10a and Fontana's frost date answer different questions.