Rio Dell, CA 95562 Frost Dates
95562, near Rio Dell, CA: the frost window
Around 03/04 is the usual last spring frost, about 188 days away. Fall's first freeze usually shows up around 11/22, roughly 264 days after the last spring frost.
Rio Dell 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
Rio Dell's growing season runs out in roughly 12 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 01/27 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/08 and only about 1 year in 10 sees frost after that.
Rio Dell against the rest of the dataset
At roughly 264 frost-free days, Rio Dell places 6,068 of 40,283 ZIP codes in this dataset. Within CA, it ranks 2,009 of 2,555.
Learn more
Two guides worth reading on 95562: zone vs. frost date, on why Zone 9b and Rio Dell's frost date answer different questions, and the frost range, on how to read the range around Rio Dell's dates instead of trusting one.