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 62903
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 62903 in zone 7a (the coldest night of a typical year: 0 to 5°F).
The nearest station, Carbondale Sewage Plant, IL, is 7 miles from the ZIP's center: its last spring frost comes after April 9 in half of years and after April 25 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 |
|---|---|---|---|---|---|---|
| Carbondale Sewage Plant, IL | 7 mi | 390 ft | April 9 | April 25 | October 22 | 6b |
| Carbondale, ILCarbondale Southern Illinois Airport | 7 mi | 406 ft | April 9 | April 25 | October 22 | 7a |
| Anna, IL2 mi NNE | 14 mi | 640 ft | April 8 | April 26 | October 29 | – |
| Du Quoin, IL4 mi SE | 22 mi | 420 ft | April 6 | April 22 | October 22 | 6b |
| Jackson, MO | 30 mi | 440 ft | April 7 | April 22 | October 29 | 7a |
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 Carbondale Sewage 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 5 | April 29 | April 22 | April 5 | October 13 | September 30 |
| 32°F | April 25 | April 16 | April 9 | March 25 | October 22 | October 10 |
| 28°F (hard freeze) | April 14 | April 4 | March 29 | March 11 | November 1 | October 19 |
| 24°F | April 2 | March 25 | March 17 | February 28 | November 13 | October 30 |
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.