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 20688
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 20688 in zone 8a (the coldest night of a typical year: 10 to 15°F).
The nearest station, Solomons, MD, is 1 miles from the ZIP's center: its last spring frost comes after March 22 in half of years and after April 5 in one year in ten.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Solomons, MD | 1 mi | 12 ft | March 22 | April 5 | November 26 | – |
| Patuxent River Naval Air Station, MD | 3 mi | 39 ft | March 29 | April 10 | November 15 | 8a |
| St Inigoes Webster NOLF, MD | 13 mi | 21 ft | March 30 | April 11 | November 14 | – |
| Mechanicsville, MD5 mi NE | 18 mi | 100 ft | April 17 | May 2 | October 27 | 7b |
| Warsaw, VA2 mi NW | 29 mi | 140 ft | April 8 | April 23 | October 30 | 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 Solomons
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 18 | April 8 | April 3 | March 20 | November 13 | October 31 |
| 32°F | April 5 | March 29 | March 22 | March 6 | November 26 | November 10 |
| 28°F (hard freeze) | March 25 | March 16 | March 10 | February 21 | December 9 | November 24 |
| 24°F | March 17 | March 6 | February 28 | February 5 | December 25 | December 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.