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 53017
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 53017 in zone 5a (the coldest night of a typical year: -20 to -15°F).
The nearest station, Richfield, WI, is 2 miles from the ZIP's center: its last spring frost comes after April 30 in half of years and after May 16 in one year in ten. By the USDA's method its plant hardiness zone is 5b.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Richfield, WI3 mi SSW | 2 mi | 984 ft | April 30 | May 16 | October 16 | 5b |
| Germantown, WI | 7 mi | 850 ft | May 6 | May 25 | October 8 | 5b |
| Jackson, WI | 9 mi | 903 ft | April 30 | May 15 | October 15 | 5b |
| Slinger, WISlinger Wastewater Treatment Plant | 9 mi | 1,029 ft | May 5 | May 20 | October 5 | – |
| Brookfield, WIBrookfield Wastewater Treatment Plant | 11 mi | 830 ft | April 30 | May 15 | October 14 | – |
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 Richfield
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 28 | May 19 | May 12 | April 28 | October 4 | September 22 |
| 32°F | May 16 | May 6 | April 30 | April 16 | October 16 | October 1 |
| 28°F (hard freeze) | May 4 | April 26 | April 19 | April 5 | October 27 | October 11 |
| 24°F | April 21 | April 12 | April 6 | March 23 | November 6 | October 26 |
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.