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 85750
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 85750 in zone 9a (the coldest night of a typical year: 20 to 25°F).
The nearest station, Tucson Camp Ave Experiment, AZ, is 6 miles from the ZIP's center: its last spring frost comes after February 20 in half of years and after March 11 in one year in ten. By the USDA's method its plant hardiness zone is 9a.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Tucson Camp Ave Experiment, AZ | 6 mi | 2,330 ft | February 20 | March 11 | November 27 | 9a |
| Tucson Weather Office, AZ | 8 mi | 2,435 ft | January 20 | February 18 | December 17 | – |
| Casas Adobes, AZTohono Chul | 8 mi | 2,527 ft | February 26 | March 18 | December 4 | – |
| Catalina, AZCatalina State Park | 10 mi | 2,707 ft | April 2 | April 18 | November 11 | – |
| Tucson U Of A #1, AZ | 10 mi | 2,315 ft | February 11 | March 7 | December 2 | 9a |
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 Tucson Camp Ave Experiment
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 21 | March 12 | February 19 | November 16 | November 1 |
| 32°F | March 11 | March 1 | February 20 | January 30 | November 27 | November 10 |
| 28°F (hard freeze) | February 24 | February 9 | January 30 | December 29 | December 10 | November 23 |
| 24°F | February 6 | January 22 | January 8 | December 9 | December 25 | December 1 |
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.