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 66611
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 66611 in zone 6b (the coldest night of a typical year: -5 to 0°F).
The nearest station, Topeka Forbes Field, KS, is 5 miles from the ZIP's center: its last spring frost comes after April 15 in half of years and after April 30 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 |
|---|---|---|---|---|---|---|
| Topeka Forbes Field, KS | 5 mi | 1,067 ft | April 15 | April 30 | October 21 | 6a |
| Topeka - NWS, KS | 5 mi | 880 ft | April 16 | April 27 | October 22 | – |
| Topeka, KSTopeka Asos | 5 mi | 876 ft | April 12 | April 27 | October 23 | 6b |
| Perry, KSPerry Lake | 17 mi | 957 ft | April 13 | April 30 | October 24 | 6a |
| Clinton Lake, KS | 20 mi | 980 ft | April 15 | May 1 | October 22 | – |
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 Topeka Forbes Field
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 11 | May 2 | April 27 | April 12 | October 11 | September 27 |
| 32°F | April 30 | April 21 | April 15 | April 2 | October 21 | October 5 |
| 28°F (hard freeze) | April 21 | April 11 | April 5 | March 21 | October 31 | October 17 |
| 24°F | April 10 | April 2 | March 27 | March 8 | November 8 | October 26 |
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.