Frost Dates for 97532 — Merlin, Oregon

Half of springs at Sexton Summit, OR see their last 32°F night by May 16; only one in ten is past it by April 23, and one in ten still has one after June 7. Planting tender crops after May 27 leaves a 30% risk of a frost on them, after June 1 20%, and after June 7 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 30 in half of years, as early as October 8 one year in ten, and holds off past November 17 one year in ten. A hard freeze of 28°F follows 18 days later, around November 17; in spring the one-in-ten date for 28°F is May 17, 21 days before the 32°F one. The freeze-free season lasts 164 days in a typical year, shorter than at 73% of the 103 Oregon stations; it reaches 197 days one year in ten and falls short of 134 one year in ten. On average 90 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 22 days longer, to about June 7, and return around October 9. Nights of 24°F, cold enough to damage hardier plants, come in 99% of winters and 16°F in 20%.

August is the warmest month at Sexton Summit, OR, averaging 77°F by day and 54°F at night; December is the coldest at 41°F and 32°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 68% of years and June still brings one in 21% of years.

Warmth for growing adds up to 1,836 growing degree days a year (base 50°F), fewer than at 71% of the 103 Oregon stations. 23% of them (414) have built up by the end of June, and August adds the most, 475. Precipitation totals 40.6 inches a year, most in December (8.1") and least in July (0.3"); May to September bring 11% of it.

The nearest other station, Grants Pass, OR, 13 miles southeast of Merlin and 2,900 feet lower, has a last frost 38 days earlier (April 8), a first frost 2 days earlier (October 28), a season 37 days longer.

Measurable snow is rare here: only 2 of 17 winters from 1991 to 2020 recorded 0.1 inch or more at Applegate, OR, 26.5 miles away, so there is no typical first-snow date to plan around.

ZIP 97532 is 8 miles from Sexton Summit, OR, which stands at 3,832 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 97532 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.