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 61603
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 61603 in zone 6a (the coldest night of a typical year: -10 to -5°F).
The nearest station, Peoria, IL, is 6 miles from the ZIP's center: its last spring frost comes after April 16 in half of years and after May 4 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 |
|---|---|---|---|---|---|---|
| Peoria, ILGeneral Wayne A. Downing International Airport | 6 mi | 650 ft | April 16 | May 4 | October 23 | 6a |
| Princeville, IL | 18 mi | 750 ft | April 22 | May 6 | October 14 | 5b |
| Congerville, IL2 mi NW | 19 mi | 640 ft | April 21 | May 7 | October 17 | 5b |
| Lacon, IL | 23 mi | 458 ft | April 20 | May 7 | October 17 | 6a |
| Bloomington, IL5 mi W | 30 mi | 852 ft | April 21 | May 5 | October 20 | 6a |
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 Peoria
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 14 | May 4 | April 27 | April 14 | October 14 | September 28 |
| 32°F | May 4 | April 23 | April 16 | April 2 | October 23 | October 9 |
| 28°F (hard freeze) | April 21 | April 11 | April 5 | March 19 | November 2 | October 21 |
| 24°F | April 10 | April 1 | March 26 | March 8 | November 13 | 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.