San Joaquin, CA 93660 Frost Dates
Frost dates for San Joaquin, CA, ZIP 93660
Around 02/27 is the usual last spring frost, about 183 days away. The first fall frost typically arrives around 11/26, about 271 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 San Joaquin, not a forecast for this year.
What to do before the first frost
Zone 9a around San Joaquin has about 13 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.
The actual range around San Joaquin's last frost
02/27 is the middle of 30 years of NOAA records, not a promise. Plant by 01/21 and you're betting against frost in roughly 9 years out of 10. 04/13 is the safer bet, historically only a 1-in-10 chance of frost that late.
How San Joaquin compares
At roughly 271 frost-free days, San Joaquin places 5,436 of 40,283 ZIP codes in this dataset. Within CA, it ranks 1,890 of 2,555.
Learn more
zone vs. frost date explains why Zone 9a and San Joaquin's frost date answer different questions, and the frost range explains how to read the range around San Joaquin's dates instead of trusting one.