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 55804
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 55804 in zone 4b (the coldest night of a typical year: -25 to -20°F).
The nearest station, Island Lake (4 mi E), MN, is 9 miles from the ZIP's center: its last spring frost comes after May 21 in half of years and after June 3 in one year in ten.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Island Lake (4 mi E), MN | 9 mi | 1,410 ft | May 21 | June 3 | September 27 | – |
| Duluth Harbor Station, MN | 13 mi | 610 ft | May 14 | June 1 | October 12 | – |
| Two Harbors, MN | 14 mi | 625 ft | May 12 | May 30 | October 6 | 4b |
| Duluth, MNDuluth International Airport | 14 mi | 1,428 ft | May 13 | May 29 | October 1 | 4b |
| Hermantown, MNDuluth NWS | 15 mi | 1,433 ft | May 18 | June 3 | October 1 | – |
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 Island Lake (4 mi E)
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 17 | June 6 | June 1 | May 20 | September 17 | September 3 |
| 32°F | June 3 | May 27 | May 21 | May 6 | September 27 | September 13 |
| 28°F (hard freeze) | May 23 | May 15 | May 7 | April 25 | October 7 | September 25 |
| 24°F | May 13 | May 2 | April 27 | April 13 | October 19 | October 5 |
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.