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 63109
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 63109 in zone 7a (the coldest night of a typical year: 0 to 5°F).
The nearest station, St Louis Science Center, MO, is 3 miles from the ZIP's center: its last spring frost comes after April 1 in half of years and after April 18 in one year in ten.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| St Louis Science Center, MO | 3 mi | 515 ft | April 1 | April 18 | November 4 | – |
| Cahokia, IL | 6 mi | 400 ft | April 6 | April 20 | October 27 | 6b |
| Cahokia Heights, ILCahokia St Louis Airport | 7 mi | 413 ft | April 8 | April 23 | October 26 | 7a |
| St. Louis, MOSt Louis Lambert International Airport | 12 mi | 531 ft | April 2 | April 17 | November 4 | 7a |
| St Charles (7 mi SSW), MO | 14 mi | 450 ft | April 4 | April 21 | 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 St Louis Science Center
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) | April 27 | April 19 | April 12 | March 27 | October 26 | October 15 |
| 32°F | April 18 | April 7 | April 1 | March 14 | November 4 | October 24 |
| 28°F (hard freeze) | April 7 | March 30 | March 22 | March 5 | November 15 | November 2 |
| 24°F | March 29 | March 17 | March 11 | February 22 | November 26 | November 9 |
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.