Frost Dates for 97396 — Willamina, Oregon

Half of springs at Laurel Mountain, OR see their last 32°F night by May 20; only one in ten is past it by April 28, and one in ten still has one after June 8. Planting tender crops after May 30 leaves a 30% risk of a frost on them, after June 2 20%, and after June 8 10%. The 19 days between the even-odds date and the one-in-ten date is narrower than at 70% of the 103 Oregon stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 23 in half of years, as early as October 5 one year in ten, and holds off past November 9 one year in ten. A hard freeze of 28°F follows 18 days later, around November 10; in spring the one-in-ten date for 28°F is May 20, 19 days before the 32°F one. The freeze-free season lasts 157 days in a typical year, shorter than at 77% of the 103 Oregon stations; it reaches 185 days one year in ten and falls short of 131 one year in ten. On average 115 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 21 days longer, to about June 10, and return around October 4. Nights of 24°F, cold enough to damage hardier plants, come in 100% of winters and 16°F in 61%.

August is the warmest month at Laurel Mountain, OR, averaging 72°F by day and 51°F at night; December is the coldest at 42°F and 31°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From July to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 79% of years and June still brings one in 23% of years.

Warmth for growing adds up to 1,262 growing degree days a year (base 50°F), fewer than at 96% of the 103 Oregon stations. 19% of them (244) have built up by the end of June, and August adds the most, 362. Precipitation totals 132.0 inches a year, most in December (23.3") and least in July (0.6"); May to September bring 11% of it.

The nearest other station, Dallas 2 NE, OR, 17 miles southeast of Willamina and 3,299 feet lower, has a last frost 34 days earlier (April 16), a first frost 9 days later (November 1), a season 42 days longer.

Measurable snow is rare here: only 9 of 27 winters from 1991 to 2020 recorded 0.1 inch or more at Willamina, OR, 4.6 miles away, so there is no typical first-snow date to plan around.

ZIP 97396 is 16 miles from Laurel Mountain, OR, which stands at 3,589 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 97396 in zone 8b, the band where the coldest night of the year averaged 15 to 20°F (-9.4 to -6.7°C) over 1991–2020; a zone describes winter lows, not frost dates.