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 53005
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 53005 in zone 5b (the coldest night of a typical year: -15 to -10°F).
The nearest station, Wauwatosa, WI, is 4 miles from the ZIP's center: its last spring frost comes after April 26 in half of years and after May 12 in one year in ten. By the USDA's method its plant hardiness zone is 6a.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Wauwatosa, WIMount Mary College | 4 mi | 715 ft | April 26 | May 12 | October 18 | 6a |
| Brookfield, WIBrookfield Wastewater Treatment Plant | 4 mi | 830 ft | April 30 | May 15 | October 14 | – |
| West Allis, WI | 6 mi | 723 ft | April 26 | May 12 | October 22 | – |
| Waukesha, WIWaukesha Wastewater Treatment Plant | 9 mi | 789 ft | May 1 | May 18 | October 13 | 5b |
| Hales Corners, WIHales Corners/Whitnall Park/Bo | 9 mi | 774 ft | May 3 | May 19 | October 14 | 5b |
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 Wauwatosa
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 24 | May 15 | May 8 | April 24 | October 6 | September 25 |
| 32°F | May 12 | May 2 | April 26 | April 12 | October 18 | October 2 |
| 28°F (hard freeze) | April 30 | April 20 | April 14 | April 1 | October 30 | October 13 |
| 24°F | April 17 | April 9 | April 4 | March 20 | November 9 | October 27 |
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.