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 47901
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 47901 in zone 6a (the coldest night of a typical year: -10 to -5°F).
The nearest station, Lafayette, IN, is 3 miles from the ZIP's center: its last spring frost comes after April 26 in half of years and after May 14 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 |
|---|---|---|---|---|---|---|
| Lafayette, INLafayette Purdue University Airport | 3 mi | 599 ft | April 26 | May 14 | October 18 | 6a |
| West Lafayette, IN6 mi NW | 7 mi | 708 ft | April 26 | May 11 | October 12 | 5b |
| Lafayette (8 mi S), IN | 8 mi | 732 ft | April 20 | May 6 | October 20 | 6a |
| Chalmers, IN5 mi W | 17 mi | 720 ft | April 25 | May 11 | October 17 | 5b |
| Delphi, IN2 mi N | 18 mi | 556 ft | April 22 | May 6 | October 17 | – |
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 Lafayette
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 13 | May 7 | April 22 | October 7 | September 24 |
| 32°F | May 14 | May 3 | April 26 | April 11 | October 18 | October 4 |
| 28°F (hard freeze) | May 1 | April 20 | April 13 | March 30 | October 28 | October 15 |
| 24°F | April 18 | April 7 | April 1 | March 15 | November 8 | October 29 |
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.