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 55121
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 55121 in zone 5a (the coldest night of a typical year: -20 to -15°F).
The nearest station, Minneapolis, MN, is 4 miles from the ZIP's center: its last spring frost comes after April 23 in half of years and after May 7 in one year in ten. By the USDA's method its plant hardiness zone is 5a.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Minneapolis, MNMinneapolis/St Paul Airport | 4 mi | 872 ft | April 23 | May 7 | October 18 | 5a |
| St Paul (3 mi SW), MN | 6 mi | 925 ft | April 25 | May 9 | October 12 | – |
| St. Paul, MNSt Paul Downtown Airport | 8 mi | 700 ft | April 24 | May 10 | October 16 | 5a |
| St Paul station, MN | 9 mi | 900 ft | April 26 | May 11 | October 12 | – |
| Rosemount, MNRosemount Research & Outreach Center | 9 mi | 945 ft | May 2 | May 16 | October 5 | 4b |
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 Minneapolis
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 17 | May 8 | May 3 | April 20 | October 6 | September 24 |
| 32°F | May 7 | April 30 | April 23 | April 8 | October 18 | October 1 |
| 28°F (hard freeze) | April 28 | April 19 | April 13 | April 1 | October 29 | October 15 |
| 24°F | April 18 | April 9 | April 4 | March 21 | November 6 | October 25 |
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.