Frost Dates for 98671 — Washougal, Washington

Half of springs at Skamania Fish Hatchery, WA see their last 32°F night by April 29; only one in ten is past it by April 5, and one in ten still has one after May 15. Planting tender crops after May 5 leaves a 30% risk of a frost on them, after May 9 20%, and after May 15 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 74% of the 113 Washington stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 22 in half of years, as early as September 27 one year in ten, and holds off past November 15 one year in ten. A hard freeze of 28°F follows 23 days later, around November 14; in spring the one-in-ten date for 28°F is May 2, 13 days before the 32°F one. The freeze-free season lasts 177 days in a typical year, shorter than at 60% of the 113 Washington stations; it reaches 211 days one year in ten and falls short of 148 one year in ten. On average 81 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 16 days longer, to about May 15, and return around October 1. Nights of 24°F, cold enough to damage hardier plants, come in 97% of winters and 16°F in 36%.

August is the warmest month at Skamania Fish Hatchery, WA, averaging 80°F by day and 50°F at night; December is the coldest at 44°F and 33°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 90% of years and May still brings one in 43% of years.

Warmth for growing adds up to 1,861 growing degree days a year (base 50°F), fewer than at 61% of the 113 Washington stations. 28% of them (515) have built up by the end of June, and August adds the most, 465. Precipitation totals 83.3 inches a year, most in November (12.4") and least in July (0.9"); May to September bring 18% of it.

The nearest other station, Troutdale, OR, 6 miles southwest of Washougal and 402 feet lower, has a last frost 34 days earlier (March 26), a first frost 26 days later (November 17), a season 60 days longer.

The first measurable snow (0.1 inch or more) in Washougal usually arrives around December 19, and the last of the season around February 23. Those are the middle dates across the winters of 1991–2020 at Skamania Fish Hatchery, WA, 3.6 miles away: half of years saw snow earlier, half later. Snow fell in 88% of those winters. The last 32°F night of spring typically comes 65 days after the last snow.

ZIP 98671 is 4 miles from Skamania Fish Hatchery, WA, which stands at 435 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 98671 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.