Rancho Cucamonga, CA 91737 Frost Dates
Rancho Cucamonga, CA: when does the frost end?
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.
Rancho Cucamonga 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
With roughly 18 weeks until Rancho Cucamonga's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 01/04 isn't a guarantee
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.
Rancho Cucamonga against the rest of the dataset
About 365 days separate Rancho Cucamonga's last and first frost, putting it 378 of 40,283 ZIP codes nationally. Within CA, it ranks 132 of 2,555.
Learn more
Before leaning on 91737's figures: the frost range explains how to read the range around Rancho Cucamonga's dates instead of trusting one, while local microclimates explains what one yard in Rancho Cucamonga can differ from the 91737 normal.