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 02451
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 02451 in zone 6b (the coldest night of a typical year: -5 to 0°F).
The nearest station, Bedford Hanscom Field, MA, is 5 miles from the ZIP's center: its last spring frost comes after April 28 in half of years and after May 12 in one year in ten. By the USDA's method its plant hardiness zone is 6a.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Bedford Hanscom Field, MA | 5 mi | 133 ft | April 28 | May 12 | October 10 | 6a |
| Bedford, MA | 6 mi | 160 ft | April 27 | May 11 | October 13 | 6b |
| Natick, MA | 9 mi | 180 ft | April 26 | May 9 | October 12 | – |
| Jamaica Plain, MA | 9 mi | 95 ft | April 19 | May 3 | October 23 | 6b |
| Maynard, MAMaynard 2 | 10 mi | 205 ft | May 2 | May 16 | October 6 | 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 Bedford Hanscom Field
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 23 | May 16 | May 10 | April 28 | October 1 | September 17 |
| 32°F | May 12 | May 3 | April 28 | April 13 | October 10 | September 28 |
| 28°F (hard freeze) | April 29 | April 19 | April 12 | April 1 | October 25 | October 7 |
| 24°F | April 11 | April 4 | April 1 | March 18 | November 5 | October 21 |
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.