Oroville, CA 95972 Frost Dates
When can you plant in Oroville, CA?
Around 05/04 is the usual last spring frost, about 249 days away. The first fall frost typically arrives around 10/30, about 174 frost-free days later.
The USDA Plant Hardiness Zone Map puts Oroville in Zone 9b (25 to 30°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
About 9 weeks of growing season left in Oroville before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
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
Oroville's growing season runs about 174 days, ranking 27,372 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 2,367 of 2,555.
Learn more
zone vs. frost date covers why Zone 9b and Oroville's frost date answer different questions. the frost range covers how to read the range around Oroville's dates instead of trusting one.