Atherton, CA 94025 Frost Dates
Atherton, CA: when does the frost end?
The last spring frost here typically falls around 02/01, about 157 days from today. Fall's first freeze usually shows up around 12/07, roughly 310 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 Atherton, not a forecast for this year.
Stretching the season past the first frost
With roughly 14 weeks until Atherton'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
02/01 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/04 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 12/28 and only about 1 year in 10 sees frost after that.
Atherton against the rest of the dataset
About 310 days separate Atherton's last and first frost, putting it 3,569 of 40,283 ZIP codes nationally. Within CA, it ranks 1,483 of 2,555.
Learn more
Before leaning on 94025's figures: local microclimates explains what one yard in Atherton can differ from the 94025 normal, while zone vs. frost date explains why Zone 9b and Atherton's frost date answer different questions.