Frost Dates for 97471 — Roseburg, Oregon

Half of springs at Roseburg Kqen, OR see their last 32°F night by March 23; only one in ten is past it by February 25, and one in ten still has one after April 16. Planting tender crops after April 1 leaves a 30% risk of a frost on them, after April 7 20%, and after April 16 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 18 in half of years, as early as October 24 one year in ten, and holds off past December 17 one year in ten. A hard freeze of 28°F follows 23 days later, around December 11; in spring the one-in-ten date for 28°F is March 21, 26 days before the 32°F one. The freeze-free season lasts 237 days in a typical year, longer than at 75% of the 103 Oregon stations; it reaches 278 days one year in ten and falls short of 203 one year in ten. On average 29 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 29 days longer, to about April 21, and return around October 25. Nights of 24°F, cold enough to damage hardier plants, come in 56% of winters and 16°F in 4%.

July is the warmest month at Roseburg Kqen, OR, averaging 88°F by day and 57°F at night; December is the coldest at 49°F and 37°F. A freezing night is all but certain in every month from December to January (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 89% of years and March still brings one in 79% of years and April still brings one in 30% of years.

Warmth for growing adds up to 3,155 growing degree days a year (base 50°F), more than at 96% of the 103 Oregon stations. 32% of them (1,002) have built up by the end of June, and July adds the most, 693. Precipitation totals 33.9 inches a year, most in December (6.3") and least in July (0.3"); May to September bring 14% of it.

The nearest other station, Roseburg Regional Airport, OR, 6 miles east of Roseburg, has a last frost 4 days earlier (March 19), a first frost 2 days later (November 20), a season 8 days longer.

Measurable snow is rare here: only 0 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Roseburg Kqen, OR, 6 miles away, so there is no typical first-snow date to plan around.

ZIP 97471 is 6 miles from Roseburg Kqen, OR, which stands at 425 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 97471 in zone 9a, the band where the coldest night of the year averaged 20 to 25°F (-6.7 to -3.9°C) over 1991–2020; a zone describes winter lows, not frost dates.