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 63301
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 63301 in zone 6b (the coldest night of a typical year: -5 to 0°F).
The nearest station, St Charles Elm Point, MO, is 4 miles from the ZIP's center: its last spring frost comes after April 8 in half of years and after April 24 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 |
|---|---|---|---|---|---|---|
| St Charles Elm Point, MO | 4 mi | 472 ft | April 8 | April 24 | October 29 | 6b |
| St. Charles, MOSt Charles County Airport | 5 mi | 436 ft | April 5 | April 21 | October 27 | 6b |
| St. Louis, MOSt Louis Lambert International Airport | 9 mi | 531 ft | April 2 | April 17 | November 4 | 7a |
| St. Peters, MOSt Peters (2 mi SE) | 9 mi | 575 ft | April 9 | April 25 | October 26 | 7a |
| St Charles (7 mi SSW), MO | 12 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 Charles Elm Point
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 5 | April 26 | April 21 | April 5 | October 19 | October 7 |
| 32°F | April 24 | April 16 | April 8 | March 23 | October 29 | October 16 |
| 28°F (hard freeze) | April 15 | April 4 | March 30 | March 9 | November 10 | October 29 |
| 24°F | April 3 | March 25 | March 16 | February 28 | November 21 | November 6 |
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.