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 03301
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 03301 in zone 5b (the coldest night of a typical year: -15 to -10°F).
The nearest station, Concord, NH, is 4 miles from the ZIP's center: its last spring frost comes after May 8 in half of years and after May 22 in one year in ten. By the USDA's method its plant hardiness zone is 5b.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Concord, NHConcord Municipal Airport | 4 mi | 346 ft | May 8 | May 22 | October 3 | 5b |
| Hopkinton Lake, NH | 10 mi | 430 ft | May 6 | May 20 | October 1 | – |
| Salisbury, NH | 12 mi | 550 ft | May 14 | May 28 | September 29 | 6a |
| Weare (2 mi NE), NH | 14 mi | 805 ft | May 9 | May 23 | October 5 | – |
| Weare, NH | 14 mi | 720 ft | May 2 | May 14 | October 8 | – |
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 Concord
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) | June 3 | May 27 | May 20 | May 7 | September 23 | September 9 |
| 32°F | May 22 | May 15 | May 8 | April 27 | October 3 | September 21 |
| 28°F (hard freeze) | May 9 | May 2 | April 27 | April 15 | October 13 | October 1 |
| 24°F | April 25 | April 19 | April 13 | April 2 | October 25 | October 10 |
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.