Lathrop, CA 95378 Frost Dates
Frost dates for Lathrop, CA, ZIP 95378
Typically, the last spring freeze lands around 02/06, roughly 162 days out. The first fall frost typically arrives around 12/01, about 304 frost-free days later.
Lathrop 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 Lathrop has about 14 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
02/06 is the middle of 30 years of NOAA records, not a promise. Plant by 02/28 and you're betting against frost in roughly 9 years out of 10. 12/31 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Lathrop compares
Lathrop's growing season runs about 304 days, ranking 3,763 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 1,528 of 2,555.
Learn more
zone vs. frost date explains why Zone 9b and Lathrop's frost date answer different questions, and the frost range explains how to read the range around Lathrop's dates instead of trusting one.