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 01850
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 01850 in zone 6b (the coldest night of a typical year: -5 to 0°F).
The nearest station, Lowell, MA, is 3 miles from the ZIP's center: its last spring frost comes after April 30 in half of years and after May 10 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 |
|---|---|---|---|---|---|---|
| Lowell, MA | 3 mi | 110 ft | April 30 | May 10 | October 10 | 6b |
| Lawrence station, MA | 8 mi | 50 ft | April 13 | April 29 | October 28 | 6b |
| Lawrence, MALawrence Municipal Airport | 10 mi | 149 ft | April 21 | May 1 | October 21 | 6b |
| Hudson, NH1 mi SSE | 10 mi | 185 ft | May 3 | May 16 | October 8 | 5b |
| Nashua, NHNashua Cwsu | 11 mi | 180 ft | April 29 | May 11 | 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 Lowell
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 21 | May 14 | May 9 | April 30 | October 1 | September 21 |
| 32°F | May 10 | May 3 | April 30 | April 19 | October 10 | September 30 |
| 28°F (hard freeze) | April 29 | April 22 | April 18 | April 7 | October 22 | October 9 |
| 24°F | April 19 | April 12 | April 6 | March 27 | November 2 | October 20 |
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.