Riverside, CA 92501 Frost Dates
Frost dates for Riverside, CA, ZIP 92501
The last spring frost here typically falls around 01/10, about 135 days from today. The first fall frost typically arrives around 01/02, about 365 frost-free days later.
The USDA Plant Hardiness Zone Map puts Riverside in Zone 10a (30 to 35°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
Zone 10a around Riverside has about 18 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
How much risk comes with planting early here
01/10 is the middle of 30 years of NOAA records, not a promise. Plant by 02/17 and you're betting against frost in roughly 9 years out of 10. 12/20 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Riverside compares
About 365 days separate Riverside's last and first frost, putting it 240 of 40,283 ZIP codes nationally. Within CA, it ranks 35 of 2,555.
Learn more
the frost range explains how to read the range around Riverside's dates instead of trusting one, and local microclimates explains what one yard in Riverside can differ from the 92501 normal.