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 85128
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 85128 in zone 9a (the coldest night of a typical year: 20 to 25°F).
The nearest station, Coolidge, AZ, is 3 miles from the ZIP's center: its last spring frost comes after February 17 in half of years and after March 8 in one year in ten.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Coolidge, AZCasa Grande National Monument | 3 mi | 1,419 ft | February 17 | March 8 | November 29 | – |
| Florence, AZ | 9 mi | 1,400 ft | January 30 | February 24 | December 12 | – |
| Eloy, AZ4 mi NE | 13 mi | 1,545 ft | February 24 | March 18 | November 28 | – |
| Robson Ranch, AZ | 13 mi | 1,495 ft | February 7 | March 4 | December 3 | – |
| Casa Grande, AZ | 13 mi | 1,400 ft | February 5 | February 28 | December 6 | – |
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 Coolidge
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 19 | March 8 | February 16 | November 19 | November 4 |
| 32°F | March 8 | February 28 | February 17 | January 22 | November 29 | November 12 |
| 28°F (hard freeze) | February 23 | February 6 | January 26 | December 26 | December 12 | November 23 |
| 24°F | February 4 | January 18 | January 7 | December 13 | December 28 | December 2 |
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.