Frost Dates for 98264 — Lynden, Washington

Half of springs at Clearbrook, WA see their last 32°F night by April 18; only one in ten is past it by March 27, and one in ten still has one after May 5. Planting tender crops after April 27 leaves a 30% risk of a frost on them, after May 1 20%, and after May 5 10%. The 17 days between the even-odds date and the one-in-ten date is narrower than at 66% of the 113 Washington stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 18 in half of years, as early as September 28 one year in ten, and holds off past November 8 one year in ten. A hard freeze of 28°F follows 20 days later, around November 7; in spring the one-in-ten date for 28°F is April 8, 27 days before the 32°F one. The freeze-free season lasts 185 days in a typical year, shorter than at 55% of the 113 Washington stations; it reaches 215 days one year in ten and falls short of 155 one year in ten. On average 57 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 19 days longer, to about May 7, and return around September 29. Nights of 24°F, cold enough to damage hardier plants, come in 100% of winters and 16°F in 51%.

July is the warmest month at Clearbrook, WA, averaging 76°F by day and 51°F at night; December is the coldest at 43°F and 32°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 80% of years and May still brings one in 21% of years.

Warmth for growing adds up to 1,712 growing degree days a year (base 50°F), fewer than at 80% of the 113 Washington stations. 31% of them (525) have built up by the end of June, and July adds the most, 422. Precipitation totals 50.0 inches a year, most in November (7.1") and least in July (1.5"); May to September bring 23% of it.

The nearest other station, Bellingham International Airport, WA, 11 miles south of Lynden, has a last frost 18 days earlier (March 31), a first frost 12 days later (October 30), a season 26 days longer.

The first measurable snow (0.1 inch or more) in Lynden usually arrives around December 19, and the last of the season around February 28. Those are the middle dates across the winters of 1991–2020 at Clearbrook, WA, 6 miles away: half of years saw snow earlier, half later. Snow fell in 95% of those winters. The last 32°F night of spring typically comes 49 days after the last snow.

ZIP 98264 is 6 miles from Clearbrook, WA, which stands at 64 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 4 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 98264 in zone 8a, the band where the coldest night of the year averaged 10 to 15°F (-12.2 to -9.4°C) over 1991–2020; a zone describes winter lows, not frost dates.