Rosemead, CA 91770 Frost Dates
Frost dates for Rosemead, CA, ZIP 91770
Around 01/04 is the usual last spring frost, about 129 days away. The first fall frost typically arrives around 01/02, about 365 frost-free days later.
Rosemead sits in USDA Zone 10b (35 to 40°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 10b around Rosemead has about 18 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
01/04 is the middle of 30 years of NOAA records, not a promise. Plant by 01/28 and you're betting against frost in roughly 9 years out of 10. 12/19 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Rosemead compares
About 365 days separate Rosemead's last and first frost, putting it 894 of 40,283 ZIP codes nationally. Within CA, it ranks 362 of 2,555.
Learn more
the frost range explains how to read the range around Rosemead's dates instead of trusting one, and local microclimates explains what one yard in Rosemead can differ from the 91770 normal.