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 21108
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 21108 in zone 7b (the coldest night of a typical year: 5 to 10°F).
The nearest station, Baltimore, MD, is 6 miles from the ZIP's center: its last spring frost comes after April 10 in half of years and after April 25 in one year in ten. By the USDA's method its plant hardiness zone is 7b.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Baltimore, MDBaltimore Wash International Airport | 6 mi | 156 ft | April 10 | April 25 | October 31 | 7b |
| Annapolis Police Barracks, MD | 9 mi | 25 ft | March 27 | April 9 | November 13 | – |
| Annapolis, MDAnnapolis Naf | 11 mi | 8 ft | March 23 | April 6 | November 20 | 8a |
| Glenn Dale, MDGlenn Dale Bell Station | 13 mi | 150 ft | April 22 | May 9 | October 22 | – |
| Maryland Science Center Baltimore, MD | 13 mi | 20 ft | March 24 | April 4 | November 21 | 8a |
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 Baltimore
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 12 | May 1 | April 24 | April 9 | October 21 | October 8 |
| 32°F | April 25 | April 16 | April 10 | March 27 | October 31 | October 17 |
| 28°F (hard freeze) | April 10 | April 2 | March 28 | March 13 | November 10 | October 30 |
| 24°F | March 31 | March 22 | March 16 | February 28 | November 25 | 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.