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 85373
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 85373 in zone 9b (the coldest night of a typical year: 25 to 30°F).
The nearest station, Youngtown, AZ, is 5 miles from the ZIP's center: its last spring frost comes after January 20 in half of years and after February 18 in one year in ten. By the USDA's method its plant hardiness zone is 9b.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Youngtown, AZ | 5 mi | 1,135 ft | January 20 | February 18 | December 15 | 9b |
| Litchfield Park, AZ | 12 mi | 1,040 ft | January 7 | February 5 | December 24 | 9b |
| Phoenix Deer Valley Municipal Airport, AZ | 13 mi | 1,455 ft | January 8 | February 12 | December 25 | 10a |
| Wittmann, AZ1 mi SE | 15 mi | 1,683 ft | February 5 | March 3 | December 11 | 9a |
| Castle Hot Springs, AZ | 22 mi | 1,990 ft | January 15 | February 21 | December 22 | 9b |
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 Youngtown
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) | March 4 | February 23 | February 14 | January 21 | December 2 | November 17 |
| 32°F | February 18 | February 2 | January 20 | December 23 | December 15 | November 28 |
| 28°F (hard freeze) | February 1 | January 12 | January 3 | December 13 | December 29 | December 10 |
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.