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 46278
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 46278 in zone 6a (the coldest night of a typical year: -10 to -5°F).
The nearest station, Indianapolis Eagle Creek Airport, IN, is 5 miles from the ZIP's center: its last spring frost comes after April 12 in half of years and after April 29 in one year in ten. By the USDA's method its plant hardiness zone is 6b.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Indianapolis Eagle Creek Airport, IN | 5 mi | 823 ft | April 12 | April 29 | October 29 | 6b |
| Whitestown, IN | 8 mi | 941 ft | April 21 | May 6 | October 20 | 6a |
| Indianapolis, INIndianapolis International Airport | 13 mi | 790 ft | April 15 | May 2 | October 26 | 6b |
| Indianapolis Nwfo, IN | 13 mi | 790 ft | April 12 | April 28 | October 27 | – |
| Castleton (2 mi S), IN | 13 mi | 824 ft | April 18 | May 6 | October 26 | 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 Indianapolis Eagle Creek Airport
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 9 | April 30 | April 23 | April 9 | October 18 | October 7 |
| 32°F | April 29 | April 19 | April 12 | March 30 | October 29 | October 16 |
| 28°F (hard freeze) | April 17 | April 6 | April 1 | March 16 | November 6 | October 27 |
| 24°F | April 5 | March 28 | March 21 | March 5 | November 18 | November 4 |
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.