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 48340
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 48340 in zone 6a (the coldest night of a typical year: -10 to -5°F).
The nearest station, Pontiac Wastewater Treatment Plant, MI, is 3 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 6b.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Pontiac Wastewater Treatment Plant, MI | 3 mi | 890 ft | April 26 | May 12 | October 22 | 6b |
| Pontiac, MIPontiac Oakland County International Airport | 7 mi | 976 ft | April 29 | May 14 | October 20 | 6a |
| White Lake (4 mi E), MI | 10 mi | 1,053 ft | May 10 | May 26 | October 6 | 5b |
| Farmington, MI | 15 mi | 720 ft | May 1 | May 16 | October 17 | 6b |
| Goodrich, MI | 20 mi | 910 ft | May 1 | May 18 | 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 Pontiac Wastewater Treatment Plant
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 22 | May 12 | May 5 | April 22 | October 10 | September 28 |
| 32°F | May 12 | May 2 | April 26 | April 15 | October 22 | October 7 |
| 28°F (hard freeze) | April 30 | April 21 | April 16 | April 3 | November 4 | October 20 |
| 24°F | April 18 | April 10 | April 4 | March 22 | November 14 | November 1 |
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.