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 46236
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 46236 in zone 6a (the coldest night of a typical year: -10 to -5°F).
The nearest station, Castleton (2 mi S), IN, is 5 miles from the ZIP's center: its last spring frost comes after April 18 in half of years and after May 6 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 |
|---|---|---|---|---|---|---|
| Castleton (2 mi S), IN | 5 mi | 824 ft | April 18 | May 6 | October 26 | 6b |
| Carmel, IN3 mi E | 7 mi | 752 ft | April 21 | May 8 | October 21 | – |
| Greenfield, IN | 13 mi | 869 ft | April 19 | May 7 | October 22 | 6a |
| Beech Grove, INIndianapolis SE Side | 14 mi | 845 ft | April 20 | May 5 | October 21 | 6b |
| Indianapolis Eagle Creek Airport, IN | 18 mi | 823 ft | April 12 | April 29 | October 29 | 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 Castleton (2 mi S)
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 16 | May 6 | April 30 | April 14 | October 16 | October 3 |
| 32°F | May 6 | April 25 | April 18 | April 3 | October 26 | October 12 |
| 28°F (hard freeze) | April 24 | April 12 | April 5 | March 21 | November 5 | October 25 |
| 24°F | April 9 | March 31 | March 25 | March 9 | November 17 | 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.