Frost Dates for 98645 — Silverlake, Washington

Half of springs at Toledo Faa Airport, WA see their last 32°F night by April 5; only one in ten is past it by March 12, and one in ten still has one after May 4. Planting tender crops after April 20 leaves a 30% risk of a frost on them, after April 27 20%, and after May 4 10%. The 29 days between the even-odds date and the one-in-ten date is wider than at 96% of the 113 Washington 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 25 in half of years, as early as September 24 one year in ten, and holds off past November 20 one year in ten. A hard freeze of 28°F follows 15 days later, around November 9; in spring the one-in-ten date for 28°F is April 8, 26 days before the 32°F one. The freeze-free season lasts 196 days in a typical year, longer than at 53% of the 113 Washington stations; it reaches 237 days one year in ten and falls short of 156 one year in ten. On average 54 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 May 2, and return around October 2. Nights of 24°F, cold enough to damage hardier plants, come in 96% of winters and 16°F in 40%.

August is the warmest month at Toledo Faa Airport, WA, averaging 81°F by day and 51°F at night; December is the coldest at 45°F and 35°F. A freezing night is all but certain in every month from December 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 50% of years and May still brings one in 16% of years.

Warmth for growing adds up to 2,092 growing degree days a year (base 50°F), more than at 57% of the 113 Washington stations. 31% of them (653) have built up by the end of June, and August adds the most, 498.

The nearest other station, Longview, WA, 13 miles southwest of Silverlake and 367 feet lower, has a last frost 3 days later (April 8), a first frost 11 days later (November 5), a season 14 days longer.

Measurable snow is rare here: only 4 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Longview, WA, 13.4 miles away, so there is no typical first-snow date to plan around.

ZIP 98645 is 12 miles from Toledo Faa Airport, WA, which stands at 379 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 98596 (Winlock). The 2023 USDA Plant Hardiness Zone Map lists ZIP 98645 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.