Clearlake, CA 95443 Frost Dates
95443, near Clearlake, CA: the frost window
Typically, the last spring freeze lands around 04/10, roughly 225 days out. Fall's first freeze usually shows up around 11/06, roughly 209 days after the last spring frost.
Clearlake sits in USDA Zone 9b (25 to 30°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.
Stretching the season past the first frost
Clearlake's growing season runs out in roughly 10 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 04/10 isn't a guarantee
04/10 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/24 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/30 and only about 1 year in 10 sees frost after that.
Clearlake against the rest of the dataset
Clearlake's growing season runs about 209 days, ranking 15,164 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 2,218 of 2,555.
Learn more
Two guides worth reading on 95443: local microclimates, on what one yard in Clearlake can differ from the 95443 normal, and zone vs. frost date, on why Zone 9b and Clearlake's frost date answer different questions.