Simi Valley, CA 93064 Frost Dates
Frost dates for Simi Valley, CA, ZIP 93064
Typically, the last spring freeze lands around 01/24, roughly 149 days out. The first fall frost typically arrives around 12/15, about 329 frost-free days later.
The USDA Plant Hardiness Zone Map puts Simi Valley in Zone 10a (30 to 35°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
Zone 10a around Simi Valley has about 16 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 01/24 isn't a guarantee
01/24 is the middle of 30 years of NOAA records, not a promise. Plant by 03/05 and you're betting against frost in roughly 9 years out of 10. 12/21 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Simi Valley compares
About 329 days separate Simi Valley's last and first frost, putting it 3,073 of 40,283 ZIP codes nationally. Within CA, it ranks 1,326 of 2,555.
Learn more
the frost range explains how to read the range around Simi Valley's dates instead of trusting one, and local microclimates explains what one yard in Simi Valley can differ from the 93064 normal.