San Bernardino, CA 92317 Frost Dates
San Bernardino, CA: when does the frost end?
Typically, the last spring freeze lands around 05/05, roughly 250 days out. Fall's first freeze usually shows up around 11/02, roughly 176 days after the last spring frost.
Zone 8a (10 to 15°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 San Bernardino, not a forecast for this year.
Stretching the season past the first frost
With roughly 9 weeks until San Bernardino's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
How much risk comes with planting early here
05/05 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/09 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/31 and only about 1 year in 10 sees frost after that.
San Bernardino against the rest of the dataset
About 176 days separate San Bernardino's last and first frost, putting it 26,319 of 40,283 ZIP codes nationally. Within CA, it ranks 2,349 of 2,555.
Learn more
Before leaning on 92317's figures: the frost range explains how to read the range around San Bernardino's dates instead of trusting one, while local microclimates explains what one yard in San Bernardino can differ from the 92317 normal.