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 61701
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 61701 in zone 6a (the coldest night of a typical year: -10 to -5°F).
The nearest station, Bloomington, IL, is 5 miles from the ZIP's center: its last spring frost comes after April 21 in half of years and after May 5 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 |
|---|---|---|---|---|---|---|
| Bloomington, IL5 mi W | 5 mi | 852 ft | April 21 | May 5 | October 20 | 6a |
| Normal, IL4 mi NE | 6 mi | 790 ft | April 25 | May 11 | October 16 | 6a |
| Congerville, IL2 mi NW | 16 mi | 640 ft | April 21 | May 7 | October 17 | 5b |
| Chenoa, IL | 23 mi | 719 ft | April 23 | May 7 | October 15 | 5b |
| Lincoln, IL | 29 mi | 583 ft | April 20 | May 4 | October 16 | 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 Bloomington
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 17 | May 8 | May 1 | April 19 | October 11 | September 27 |
| 32°F | May 5 | April 26 | April 21 | April 7 | October 20 | October 9 |
| 28°F (hard freeze) | April 23 | April 15 | April 9 | March 26 | October 30 | October 18 |
| 24°F | April 12 | April 4 | March 31 | March 12 | November 8 | October 28 |
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.