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 85709
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 85709 in zone 9b (the coldest night of a typical year: 25 to 30°F).
The nearest station, Tucson, AZ, is 2 miles from the ZIP's center: its last spring frost comes after February 5 in half of years and after March 2 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 |
|---|---|---|---|---|---|---|
| Tucson, AZTucson International Airport | 2 mi | 2,549 ft | February 5 | March 2 | December 9 | 9b |
| Tucson Weather Office, AZ | 6 mi | 2,435 ft | January 20 | February 18 | December 17 | – |
| Tucson U Of A #1, AZ | 8 mi | 2,315 ft | February 11 | March 7 | December 2 | 9a |
| Tucson Camp Ave Experiment, AZ | 10 mi | 2,330 ft | February 20 | March 11 | November 27 | 9a |
| Tucson (11 mi W), AZ | 12 mi | 2,733 ft | February 8 | March 8 | December 10 | – |
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
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 24 | March 7 | February 28 | February 3 | November 26 | November 11 |
| 32°F | March 2 | February 17 | February 5 | January 4 | December 9 | November 21 |
| 28°F (hard freeze) | February 17 | January 31 | January 11 | December 14 | December 26 | November 30 |
| 24°F | February 7 | January 20 | January 5 | December 12 | January 3 | 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.