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 85748
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 85748 in zone 9a (the coldest night of a typical year: 20 to 25°F).
The nearest station, Saguaro National Park, AZ, is 3 miles from the ZIP's center: its last spring frost comes after January 26 in half of years and after February 25 in one year in ten.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Saguaro National Park, AZ | 3 mi | 3,080 ft | January 26 | February 25 | December 16 | – |
| Tucson Weather Office, AZ | 12 mi | 2,435 ft | January 20 | February 18 | December 17 | – |
| Mount Lemmon Willow Canyon, AZ | 12 mi | 7,027 ft | April 1 | April 21 | November 19 | – |
| Tucson Camp Ave Experiment, AZ | 12 mi | 2,330 ft | February 20 | March 11 | November 27 | 9a |
| Tucson, AZTucson International Airport | 13 mi | 2,549 ft | February 5 | March 2 | December 9 | 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 Saguaro National Park
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 18 | March 4 | February 22 | January 22 | December 2 | November 16 |
| 32°F | February 25 | February 6 | January 26 | December 24 | December 16 | November 26 |
| 28°F (hard freeze) | February 9 | January 25 | January 7 | December 14 | December 28 | December 9 |
| 24°F | February 8 | January 13 | January 6 | December 17 | January 5 | December 17 |
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.