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 80921
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 80921 in zone 5b (the coldest night of a typical year: -15 to -10°F).
The nearest station, Black Forest, CO, is 2 miles from the ZIP's center: its last spring frost comes after May 11 in half of years and after May 25 in one year in ten. By the USDA's method its plant hardiness zone is 6a.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Black Forest, CO6 mi WNW | 2 mi | 6,957 ft | May 11 | May 25 | October 6 | 6a |
| Monument, CO3 mi S | 3 mi | 6,821 ft | May 17 | May 30 | October 1 | – |
| Monument station, CO | 4 mi | 7,080 ft | May 14 | May 31 | October 1 | – |
| Cumbre Vista - Colorado Springs 1, CO | 10 mi | 6,942 ft | May 9 | May 20 | October 6 | – |
| Eastonville (2 mi NNW), CO | 12 mi | 7,210 ft | May 29 | June 13 | September 21 | – |
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 Black Forest
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) | June 5 | May 28 | May 23 | May 10 | September 29 | September 17 |
| 32°F | May 25 | May 16 | May 11 | April 30 | October 6 | September 25 |
| 28°F (hard freeze) | May 16 | May 7 | May 2 | April 19 | October 16 | October 3 |
| 24°F | May 8 | April 29 | April 22 | April 6 | October 24 | October 11 |
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.