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 92411
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 92411 in zone 10a (the coldest night of a typical year: 30 to 35°F).
The nearest station, Redlands, CA, is 10 miles from the ZIP's center: its last spring frost comes after January 27 in half of years and after February 28 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 |
|---|---|---|---|---|---|---|
| Redlands, CA | 10 mi | 1,410 ft | January 27 | February 28 | December 19 | 10a |
| Riverside Citrus Experiment, CA | 11 mi | 986 ft | January 10 | February 17 | January 2 | 10a |
| Lake Arrowhead, CA | 12 mi | 5,205 ft | May 5 | May 31 | November 2 | – |
| Riverside Fire Station 3, CA | 12 mi | 840 ft | January 9 | February 25 | December 25 | – |
| Riverside, CARiverside Municipal Airport | 13 mi | 805 ft | January 9 | February 21 | December 30 | 10a |
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 Redlands
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 5 | March 13 | March 2 | January 31 | December 2 | November 17 |
| 32°F | February 28 | February 10 | January 27 | December 21 | December 19 | December 1 |
| 28°F (hard freeze) | February 15 | January 28 | January 7 | December 17 | January 1 | December 13 |
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.