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 21801
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 21801 in zone 7b (the coldest night of a typical year: 5 to 10°F).
The nearest station, Salisbury station, MD, is 5 miles from the ZIP's center: its last spring frost comes after April 3 in half of years and after April 25 in one year in ten. By the USDA's method its plant hardiness zone is 8a.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Salisbury station, MD | 5 mi | 10 ft | April 3 | April 25 | November 7 | 8a |
| Salisbury (2 mi N), MD | 6 mi | 20 ft | April 2 | April 16 | November 10 | – |
| Salisbury, MDSalisbury-Wicomico Regional Airport | 9 mi | 48 ft | April 10 | April 30 | October 30 | 7b |
| Vienna, MD | 12 mi | 10 ft | April 8 | April 23 | November 4 | – |
| Snow Hill, MD4 mi N | 18 mi | 30 ft | April 10 | April 28 | October 31 | 7b |
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 Salisbury station
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 8 | April 24 | April 17 | March 31 | October 27 | October 14 |
| 32°F | April 25 | April 9 | April 3 | March 18 | November 7 | October 27 |
| 28°F (hard freeze) | April 6 | March 29 | March 21 | March 4 | November 21 | November 4 |
| 24°F | March 27 | March 17 | March 10 | February 20 | December 5 | November 18 |
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.