Frost Dates for 97317 — Salem, Oregon

Half of springs at Salem Mcnary Field, OR see their last 32°F night by April 3; only one in ten is past it by March 10, and one in ten still has one after April 27. Planting tender crops after April 13 leaves a 30% risk of a frost on them, after April 19 20%, and after April 27 10%. The 24 days between the even-odds date and the one-in-ten date is wider than at 60% 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 November 1 in half of years, as early as October 16 one year in ten, and holds off past November 23 one year in ten. A hard freeze of 28°F follows 21 days later, around November 22; in spring the one-in-ten date for 28°F is March 30, 28 days before the 32°F one. The freeze-free season lasts 212 days in a typical year, longer than at 58% of the 103 Oregon stations; it reaches 245 days one year in ten and falls short of 183 one year in ten. On average 49 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 27 days longer, to about April 30, and return around October 18. Nights of 24°F, cold enough to damage hardier plants, come in 93% of winters and 16°F in 16%.

July is the warmest month at Salem Mcnary Field, OR, averaging 84°F by day and 55°F at night; December is the coldest at 47°F and 35°F. A freezing night is all but certain in every month from December to February (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, March still brings one in 89% of years and April still brings one in 54% of years.

Warmth for growing adds up to 2,568 growing degree days a year (base 50°F), more than at 72% of the 103 Oregon stations. 29% of them (756) have built up by the end of June, and July adds the most, 598. Precipitation totals 40.4 inches a year, most in December (7.0") and least in July (0.3"); May to September bring 14% of it.

The nearest other station, Stayton, OR, 8 miles southeast of Salem and 220 feet higher, has a last frost 5 days earlier (March 29), a first frost 5 days later (November 6), a season 10 days longer.

Measurable snow is rare here: only 5 of 27 winters from 1991 to 2020 recorded 0.1 inch or more at Stayton, OR, 8.5 miles away, so there is no typical first-snow date to plan around.

ZIP 97317 is 5 miles from Salem Mcnary Field, OR, which stands at 205 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 6 other ZIP codes share the station; its figures are presented in full for 97301 (Salem). The 2023 USDA Plant Hardiness Zone Map lists ZIP 97317 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.