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 46628
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 46628 in zone 6a (the coldest night of a typical year: -10 to -5°F).
The nearest station, South Bend, IN, is 1 miles from the ZIP's center: its last spring frost comes after May 1 in half of years and after May 17 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 |
|---|---|---|---|---|---|---|
| South Bend, INSouth Bend Airport | 1 mi | 773 ft | May 1 | May 17 | October 19 | 6a |
| South Bend station, IN | 4 mi | 710 ft | April 23 | May 9 | October 23 | – |
| Niles, MI | 9 mi | 650 ft | April 27 | May 14 | October 25 | – |
| Lakeville, IN | 14 mi | 841 ft | May 1 | May 18 | October 13 | 5b |
| Dowagiac, MI1 mi W | 21 mi | 740 ft | May 4 | May 22 | October 11 | 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 South Bend
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 27 | May 18 | May 11 | April 27 | October 7 | September 25 |
| 32°F | May 17 | May 7 | May 1 | April 16 | October 19 | October 5 |
| 28°F (hard freeze) | May 5 | April 25 | April 19 | April 4 | October 31 | October 19 |
| 24°F | April 21 | April 14 | April 7 | March 26 | November 12 | 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.