Frost dates by ZIP code: The nearest NOAA stations to your ZIP, 1991-2020 normals
Enter a five-digit ZIP code. PlainClimate finds its center (Census Bureau 2024) and the five nearest NOAA stations with frost dates, and shows each station's last spring and first autumn 32°F dates with its distance and elevation.
Frost dates near ZIP 94947
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 94947 in zone 9b (the coldest night of a typical year: 25 to 30°F).
The nearest station, San Rafael, CA, is 9 miles from the ZIP's center: its last spring frost comes after January 11 in half of years and after February 25 in one year in ten. By the USDA's method its plant hardiness zone is 10a.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| San Rafael, CASan Rafael Civic Center | 9 mi | 120 ft | January 11 | February 25 | December 21 | 10a |
| Petaluma, CAPetaluma Airport | 11 mi | 20 ft | February 28 | April 6 | November 25 | 9b |
| Kentfield, CA | 11 mi | 145 ft | January 16 | February 25 | December 18 | 10a |
| Sonoma, CA | 16 mi | 97 ft | March 2 | April 5 | November 27 | 9b |
| Richmond, CA | 19 mi | 20 ft | January 4 | January 26 | January 2 | – |
Frost comes later in spring at higher and colder stations and earlier in low, open ground: prefer a station at a similar elevation to yours. Hardiness zone in the table: the USDA's rule (the average of each year's coldest night, 1991-2020) applied to the station's own record.
Every frost threshold at San Rafael
NOAA publishes the dates for several temperatures and odds. A 30% spring date means a 3-in-10 chance of a later frost (the convention almanacs use); 50% is the median; 10% the cautious date.
| Threshold | Spring, 10% | Spring, 30% | Spring, 50% | Spring, 90% | Autumn, 50% | Autumn, 10% |
|---|---|---|---|---|---|---|
| 36°F (light frost) | April 6 | March 6 | February 22 | January 6 | December 5 | November 15 |
| 32°F | February 25 | February 1 | January 11 | December 14 | December 21 | December 2 |
| 28°F (hard freeze) | February 21 | January 22 | December 31 | December 11 | December 29 | December 7 |
Source: NOAA NCEI 1991-2020 annual normals; ZIP centers: Census Bureau 2024 Gazetteer; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. Autumn 10%: one year in ten has its first frost before this date.