Poway, CA 92174 Frost Dates
92174, near Poway, CA: the frost window
Typically, the last spring freeze lands around 03/04, roughly 188 days out. Fall's first freeze usually shows up around 12/04, roughly 270 days after the last spring frost.
Zone 10b (35 to 40°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 Poway, not a forecast for this year.
Stretching the season past the first frost
Poway's growing season runs out in roughly 14 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 03/04 isn't a guarantee
03/04 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 01/29 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/10 and only about 1 year in 10 sees frost after that.
Poway against the rest of the dataset
Poway's growing season runs about 270 days, ranking 5,540 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 1,960 of 2,555.
Learn more
Two guides worth reading on 92174: zone vs. frost date, on why Zone 10b and Poway's frost date answer different questions, and the frost range, on how to read the range around Poway's dates instead of trusting one.