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 97504
The USDA's 2023 Plant Hardiness Zone Map puts ZIP 97504 in zone 8b (the coldest night of a typical year: 15 to 20°F).
The nearest station, Medford, OR, is 5 miles from the ZIP's center: its last spring frost comes after April 8 in half of years and after April 30 in one year in ten. By the USDA's method its plant hardiness zone is 8b.
| Station | Distance | Elevation | Last frost (median) | 1 in 10 after | First frost (median) | Hardiness zone |
|---|---|---|---|---|---|---|
| Medford, ORMedford International Airport | 5 mi | 1,297 ft | April 8 | April 30 | October 29 | 8b |
| Ashland, OR | 9 mi | 1,729 ft | May 6 | May 27 | October 8 | 8a |
| Ruch, OR | 15 mi | 1,550 ft | May 4 | May 23 | October 13 | – |
| Howard Prairie Dam, OR | 22 mi | 4,567 ft | June 8 | June 25 | September 24 | 7a |
| Lost Creek Dam, OR | 25 mi | 1,580 ft | April 29 | May 19 | October 17 | 8a |
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 Medford
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 17 | May 6 | April 30 | April 11 | October 16 | October 3 |
| 32°F | April 30 | April 18 | April 8 | March 17 | October 29 | October 14 |
| 28°F (hard freeze) | April 3 | March 21 | March 10 | February 16 | November 13 | October 26 |
| 24°F | March 3 | February 20 | February 10 | December 28 | December 3 | November 7 |
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.