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 45503
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 45503 in zone 6a (the coldest night of a typical year: -10 to -5°F).
The nearest station, Springfield, OH, is 2 miles from the ZIP's center: its last spring frost comes after April 25 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 |
|---|---|---|---|---|---|---|
| Springfield, OHSpringfield Water Treatment Plant | 2 mi | 951 ft | April 25 | May 12 | October 19 | 6a |
| Urbana, OHUrbana Wastewater Treatment Plant | 9 mi | 1,019 ft | April 24 | May 10 | October 19 | 6b |
| New Carlisle, OH | 14 mi | 874 ft | April 24 | May 10 | October 17 | – |
| London, OHLondon Fish Hatchery | 14 mi | 1,120 ft | April 24 | May 10 | October 18 | – |
| Dayton, OHDayton International Airport | 24 mi | 1,000 ft | April 16 | May 3 | October 28 | 6b |
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 Springfield
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 20 | May 10 | May 5 | April 22 | October 6 | September 23 |
| 32°F | May 12 | May 2 | April 25 | April 12 | October 19 | October 4 |
| 28°F (hard freeze) | April 30 | April 21 | April 15 | March 31 | October 30 | October 16 |
| 24°F | April 19 | April 9 | April 3 | March 19 | November 7 | 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.