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 85650
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 85650 in zone 8b (the coldest night of a typical year: 15 to 20°F).
The nearest station, Sierra Vista, AZ, is 5 miles from the ZIP's center: its last spring frost comes after April 5 in half of years and after April 21 in one year in ten.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Sierra Vista, AZ | 5 mi | 4,606 ft | April 5 | April 21 | November 9 | – |
| Coronado National Memorial, AZ | 11 mi | 5,242 ft | April 7 | April 27 | November 9 | 8b |
| Fort Huachuca Pioneer Airfield, AZ | 15 mi | 4,768 ft | March 16 | April 12 | November 21 | – |
| Bisbee, AZ1 mi WNW | 16 mi | 5,560 ft | April 1 | April 20 | November 10 | – |
| Tombstone, AZ | 17 mi | 4,659 ft | March 4 | March 31 | November 29 | 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 Sierra Vista
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) | May 4 | April 27 | April 20 | April 5 | October 30 | October 15 |
| 32°F | April 21 | April 11 | April 5 | March 15 | November 9 | October 23 |
| 28°F (hard freeze) | April 5 | March 25 | March 15 | February 21 | November 21 | November 4 |
| 24°F | March 15 | March 1 | February 19 | January 20 | December 3 | November 16 |
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.