Norco, CA 92505 Frost Dates
Frost dates for Norco, CA, ZIP 92505
Typically, the last spring freeze lands around 01/09, roughly 134 days out. The first fall frost typically arrives around 12/30, about 362 frost-free days later.
The USDA Plant Hardiness Zone Map puts Norco 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 Norco 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.
Why 01/09 isn't a guarantee
01/09 is the middle of 30 years of NOAA records, not a promise. Plant by 02/21 and you're betting against frost in roughly 9 years out of 10. 12/16 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Norco compares
Norco's growing season runs about 362 days, ranking 2,069 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 955 of 2,555.
Learn more
local microclimates explains what one yard in Norco can differ from the 92505 normal, and zone vs. frost date explains why Zone 10a and Norco's frost date answer different questions.