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 63033
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 63033 in zone 7a (the coldest night of a typical year: 0 to 5°F).
The nearest station, St. Louis, MO, is 6 miles from the ZIP's center: its last spring frost comes after April 2 in half of years and after April 17 in one year in ten. By the USDA's method its plant hardiness zone is 7a.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| St. Louis, MOSt Louis Lambert International Airport | 6 mi | 531 ft | April 2 | April 17 | November 4 | 7a |
| Alton, ILAlton - Melvin Price Lock and Dam | 8 mi | 405 ft | April 4 | April 19 | November 5 | – |
| St Louis Science Center, MO | 12 mi | 515 ft | April 1 | April 18 | November 4 | – |
| St. Charles, MOSt Charles County Airport | 12 mi | 436 ft | April 5 | April 21 | October 27 | 6b |
| St Charles Elm Point, MO | 13 mi | 472 ft | April 8 | April 24 | 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
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 28 | April 19 | April 13 | March 31 | October 26 | October 14 |
| 32°F | April 17 | April 7 | April 2 | March 17 | November 4 | October 23 |
| 28°F (hard freeze) | April 7 | March 31 | March 23 | March 5 | November 13 | November 2 |
| 24°F | March 29 | March 18 | March 12 | February 24 | November 24 | November 8 |
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.