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 18017
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 18017 in zone 7a (the coldest night of a typical year: 0 to 5°F).
The nearest station, Allentown, PA, is 3 miles from the ZIP's center: its last spring frost comes after April 20 in half of years and after May 6 in one year in ten. By the USDA's method its plant hardiness zone is 7a.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Allentown, PAAllentown Lehigh Valley International Airport | 3 mi | 390 ft | April 20 | May 6 | October 24 | 7a |
| Springtown (1 mi NNE), PA | 8 mi | 860 ft | April 21 | May 6 | October 22 | 7a |
| Phillipsburg, NJPhillipsburg-Easton Bridge | 10 mi | 232 ft | April 18 | May 5 | October 25 | 7a |
| Bucksville, PA | 15 mi | 387 ft | April 29 | May 15 | October 16 | 6b |
| Rodale Research Center, PA | 19 mi | 550 ft | April 26 | May 13 | October 14 | – |
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 Allentown
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 18 | May 9 | May 2 | April 19 | October 12 | September 29 |
| 32°F | May 6 | April 26 | April 20 | April 6 | October 24 | October 8 |
| 28°F (hard freeze) | April 18 | April 10 | April 5 | March 23 | November 4 | October 19 |
| 24°F | April 6 | March 31 | March 26 | March 10 | November 16 | 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.