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 40242
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 40242 in zone 7a (the coldest night of a typical year: 0 to 5°F).
The nearest station, Louisville Bowman Field, KY, is 5 miles from the ZIP's center: its last spring frost comes after April 3 in half of years and after April 19 in one year in ten. By the USDA's method its plant hardiness zone is 7b.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Louisville Bowman Field, KY | 5 mi | 540 ft | April 3 | April 19 | November 3 | 7b |
| Louisville, KYLouisville International Airport | 11 mi | 488 ft | March 31 | April 16 | November 7 | 7a |
| Crestwood, KY4 mi NE | 11 mi | 780 ft | April 12 | May 1 | October 25 | – |
| Louisville McAlpine, KY | 11 mi | 440 ft | March 31 | April 14 | November 9 | – |
| Louisville Weather Office, KY | 12 mi | 632 ft | April 6 | April 23 | November 1 | – |
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 Louisville Bowman Field
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 3 | April 22 | April 16 | April 2 | October 23 | October 12 |
| 32°F | April 19 | April 9 | April 3 | March 18 | November 3 | October 21 |
| 28°F (hard freeze) | April 5 | March 29 | March 22 | March 4 | November 13 | November 1 |
| 24°F | March 26 | March 18 | March 9 | February 20 | November 24 | November 8 |
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.