Simi Valley, CA 93065 Frost Dates
Simi Valley, CA: when does the frost end?
Typically, the last spring freeze lands around 01/24, roughly 149 days out. Fall's first freeze usually shows up around 12/15, roughly 329 days after the last spring frost.
Zone 10a (30 to 35°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 Simi Valley, not a forecast for this year.
Stretching the season past the first frost
With roughly 16 weeks until Simi Valley's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
How much risk comes with planting early here
01/24 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/05 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 12/21 and only about 1 year in 10 sees frost after that.
Simi Valley against the rest of the dataset
About 329 days separate Simi Valley's last and first frost, putting it 3,074 of 40,283 ZIP codes nationally. Within CA, it ranks 1,327 of 2,555.
Learn more
Before leaning on 93065's figures: zone vs. frost date explains why Zone 10a and Simi Valley's frost date answer different questions, while the frost range explains how to read the range around Simi Valley's dates instead of trusting one.