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 55904
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 55904 in zone 4b (the coldest night of a typical year: -25 to -20°F).
The nearest station, Rochester, MN, is 6 miles from the ZIP's center: its last spring frost comes after April 30 in half of years and after May 13 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 |
|---|---|---|---|---|---|---|
| Rochester, MNRochester International Airport | 6 mi | 1,304 ft | April 30 | May 13 | October 6 | 5a |
| Byron, MNByron 4NORTH | 15 mi | 1,041 ft | May 12 | May 25 | September 28 | – |
| Grand Meadow, MN | 19 mi | 1,350 ft | May 6 | May 18 | October 1 | 4b |
| Theilman (1 mi SSW), MN | 25 mi | 753 ft | May 7 | May 22 | October 2 | 4a |
| Preston, MN | 25 mi | 930 ft | May 14 | May 27 | September 28 | 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 Rochester
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 14 | May 9 | April 28 | September 28 | September 14 |
| 32°F | May 13 | May 5 | April 30 | April 15 | October 6 | September 22 |
| 28°F (hard freeze) | May 2 | April 25 | April 18 | April 4 | October 17 | October 4 |
| 24°F | April 24 | April 15 | April 9 | March 24 | October 28 | October 13 |
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.