Oroville, CA 95941 Frost Dates
Frost dates for Oroville, CA, ZIP 95941
The last spring frost here typically falls around 05/04, about 249 days from today. The first fall frost typically arrives around 10/30, about 174 frost-free days later.
Zone 9a (20 to 25°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 Oroville, not a forecast for this year.
What to do before the first frost
Zone 9a around Oroville has about 9 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 05/04 isn't a guarantee
05/04 is the middle of 30 years of NOAA records, not a promise. Plant by 04/18 and you're betting against frost in roughly 9 years out of 10. 05/31 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Oroville compares
About 174 days separate Oroville's last and first frost, putting it 27,371 of 40,283 ZIP codes nationally. Within CA, it ranks 2,366 of 2,555.
Learn more
the frost range explains how to read the range around Oroville's dates instead of trusting one, and local microclimates explains what one yard in Oroville can differ from the 95941 normal.