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 03103
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 03103 in zone 6a (the coldest night of a typical year: -10 to -5°F).
The nearest station, Manchester, NH, is 2 miles from the ZIP's center: its last spring frost comes after April 21 in half of years and after May 6 in one year in ten. By the USDA's method its plant hardiness zone is 6b.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Manchester, NHManchester Airport | 2 mi | 225 ft | April 21 | May 6 | October 19 | 6b |
| Massabesic Lake, NH | 3 mi | 253 ft | April 30 | May 14 | October 11 | 5b |
| Nashua (2 mi NNW), NH | 11 mi | 135 ft | April 30 | May 11 | October 12 | 6a |
| Hudson, NH1 mi SSE | 12 mi | 185 ft | May 3 | May 16 | October 8 | 5b |
| West Hampstead, NH | 13 mi | 288 ft | April 30 | May 14 | October 11 | 6a |
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 Manchester
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 19 | May 9 | May 4 | April 23 | October 7 | September 28 |
| 32°F | May 6 | April 27 | April 21 | April 8 | October 19 | October 4 |
| 28°F (hard freeze) | April 21 | April 13 | April 7 | March 28 | November 1 | October 16 |
| 24°F | April 7 | April 1 | March 29 | March 15 | November 15 | November 1 |
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.