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 17103
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 17103 in zone 7a (the coldest night of a typical year: 0 to 5°F).
The nearest station, Harrisburg (1 mi NE), PA, is 1 miles from the ZIP's center: its last spring frost comes after April 15 in half of years and after May 2 in one year in ten. By the USDA's method its plant hardiness zone is 7b.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Harrisburg (1 mi NE), PA | 1 mi | 420 ft | April 15 | May 2 | October 23 | 7b |
| Harrisburg, PAHarrisburg Capitol Cy Airport | 4 mi | 340 ft | April 9 | April 25 | November 1 | 7b |
| Middletown, PAMiddletown Harrisburg Int'l Airport | 8 mi | 312 ft | April 9 | April 25 | November 2 | 7a |
| Dehart Dam, PA | 14 mi | 537 ft | May 1 | May 20 | October 16 | 7a |
| Carlisle, PACarlisle Water Treatment Plant | 18 mi | 430 ft | April 23 | May 9 | October 18 | – |
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 Harrisburg (1 mi NE)
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 15 | May 6 | April 30 | April 14 | October 12 | September 28 |
| 32°F | May 2 | April 21 | April 15 | April 1 | October 23 | October 7 |
| 28°F (hard freeze) | April 16 | April 8 | April 3 | March 19 | November 5 | October 20 |
| 24°F | April 3 | March 29 | March 22 | March 6 | November 17 | 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.