Frost Dates for 97862 — Milton Freewater, Oregon

Half of springs at Milton Freewater, OR see their last 32°F night by March 25; only one in ten is past it by March 6, and one in ten still has one after April 16. Planting tender crops after April 3 leaves a 30% risk of a frost on them, after April 8 20%, and after April 16 10%. The 22 days between the even-odds date and the one-in-ten date is narrower than at 45% of the 103 Oregon stations behind this site's ZIP pages, so a fixed calendar date is a gamble here.

In fall the first 32°F night comes by October 29 in half of years, as early as October 12 one year in ten, and holds off past November 16 one year in ten. A hard freeze of 28°F follows 13 days later, around November 11; in spring the one-in-ten date for 28°F is March 28, 19 days before the 32°F one. The freeze-free season lasts 218 days in a typical year, longer than at 62% of the 103 Oregon stations; it reaches 243 days one year in ten and falls short of 191 one year in ten. On average 74 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 25 days longer, to about April 19, and return around October 17. Nights of 24°F, cold enough to damage hardier plants, come in 100% of winters and 16°F in 86%.

July is the warmest month at Milton Freewater, OR, averaging 90°F by day and 63°F at night; December is the coldest at 44°F and 30°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 34% of years.

Warmth for growing adds up to 3,513 growing degree days a year (base 50°F), the most of the 103 Oregon stations. 33% of them (1,143) have built up by the end of June, and July adds the most, 829. Precipitation totals 16.2 inches a year, most in December (2.1") and least in July (0.3"); May to September bring 27% of it.

The nearest other station, Whitman Mission, WA, 9 miles northwest of Milton Freewater and 338 feet lower, has a last frost 38 days later (May 2), a first frost 28 days earlier (October 1), a season 67 days shorter.

The first measurable snow (0.1 inch or more) in Milton Freewater usually arrives around December 11, and the last of the season around February 10. Those are the middle dates across the winters of 1991–2020 at Whitman Mission, WA, 8.5 miles away: half of years saw snow earlier, half later. Snow fell in 95% of those winters. The last 32°F night of spring typically comes 43 days after the last snow.

ZIP 97862 is 2 miles from Milton Freewater, OR, which stands at 970 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 97862 in zone 7a, the band where the coldest night of the year averaged 0 to 5°F (-17.8 to -15.0°C) over 1991–2020; a zone describes winter lows, not frost dates.