Rio Dell, CA 95560 Frost Dates
Rio Dell, CA: when does the frost end?
The last spring frost here typically falls around 03/10, about 194 days from today. Fall's first freeze usually shows up around 12/01, roughly 271 days after the last spring frost.
Zone 9b (25 to 30°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 Rio Dell, not a forecast for this year.
Stretching the season past the first frost
With roughly 14 weeks until Rio Dell's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 03/10 isn't a guarantee
03/10 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 01/09 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/13 and only about 1 year in 10 sees frost after that.
Rio Dell against the rest of the dataset
At roughly 271 frost-free days, Rio Dell places 5,442 of 40,283 ZIP codes in this dataset. Within CA, it ranks 1,896 of 2,555.
Learn more
Before leaning on 95560's figures: zone vs. frost date explains why Zone 9b and Rio Dell's frost date answer different questions, while the frost range explains how to read the range around Rio Dell's dates instead of trusting one.