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 61704
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 61704 in zone 6a (the coldest night of a typical year: -10 to -5°F).
The nearest station, Normal, IL, is 5 miles from the ZIP's center: its last spring frost comes after April 25 in half of years and after May 11 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 |
|---|---|---|---|---|---|---|
| Normal, IL4 mi NE | 5 mi | 790 ft | April 25 | May 11 | October 16 | 6a |
| Bloomington, IL5 mi W | 8 mi | 852 ft | April 21 | May 5 | October 20 | 6a |
| Congerville, IL2 mi NW | 19 mi | 640 ft | April 21 | May 7 | October 17 | 5b |
| Chenoa, IL | 22 mi | 719 ft | April 23 | May 7 | October 15 | 5b |
| Gibson City, IL | 30 mi | 750 ft | April 21 | May 5 | October 17 | 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 Normal
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 22 | May 11 | May 4 | April 21 | October 5 | September 23 |
| 32°F | May 11 | May 1 | April 25 | April 11 | October 16 | October 2 |
| 28°F (hard freeze) | May 1 | April 21 | April 14 | April 1 | October 27 | October 12 |
| 24°F | April 21 | April 9 | April 3 | March 18 | November 6 | October 25 |
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.