Williams, CA 95637 Frost Dates
Frost dates for Williams, CA, ZIP 95637
The last spring frost here typically falls around 04/10, about 225 days from today. The first fall frost typically arrives around 11/06, about 209 frost-free days later.
Williams sits in USDA Zone 9b (25 to 30°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
What to do before the first frost
Zone 9b around Williams has about 10 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 04/10 isn't a guarantee
04/10 is the middle of 30 years of NOAA records, not a promise. Plant by 03/24 and you're betting against frost in roughly 9 years out of 10. 04/30 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Williams compares
Williams's growing season runs about 209 days, ranking 15,208 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 2,228 of 2,555.
Learn more
zone vs. frost date explains why Zone 9b and Williams's frost date answer different questions, and the frost range explains how to read the range around Williams's dates instead of trusting one.