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 55409
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 55409 in zone 5a (the coldest night of a typical year: -20 to -15°F).
The nearest station, Lower St Anthony Falls, 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 |
|---|---|---|---|---|---|---|
| Lower St Anthony Falls, MN | 4 mi | 754 ft | April 23 | May 7 | October 16 | 5a |
| 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 | – |
| University of Minnesota St Paul, MN | 6 mi | 970 ft | April 28 | May 14 | October 8 | 5a |
| New Hope, MN | 7 mi | 910 ft | April 29 | May 12 | October 12 | 5a |
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 Lower St Anthony Falls
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 21 | May 10 | May 4 | April 20 | October 5 | September 23 |
| 32°F | May 7 | April 30 | April 23 | April 10 | October 16 | October 2 |
| 28°F (hard freeze) | April 27 | April 20 | April 14 | April 2 | October 27 | October 12 |
| 24°F | April 19 | April 11 | April 5 | March 22 | November 5 | October 21 |
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.