Frost Dates for 98248 — Ferndale, Washington

Half of springs at Bellingham International Airport, WA see their last 32°F night by March 31; only one in ten is past it by March 10, and one in ten still has one after April 18. Planting tender crops after April 6 leaves a 30% risk of a frost on them, after April 12 20%, and after April 18 10%. The 18 days between the even-odds date and the one-in-ten date is narrower than at 56% of the 113 Washington stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 30 in half of years, as early as October 12 one year in ten, and holds off past November 17 one year in ten. A hard freeze of 28°F follows 17 days later, around November 16; in spring the one-in-ten date for 28°F is March 25, 24 days before the 32°F one. The freeze-free season lasts 211 days in a typical year, longer than at 68% of the 113 Washington stations; it reaches 240 days one year in ten and falls short of 187 one year in ten. On average 59 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 25 days longer, to about April 25, and return around October 13. Nights of 24°F, cold enough to damage hardier plants, come in 98% of winters and 16°F in 40%.

August is the warmest month at Bellingham International Airport, WA, averaging 73°F by day and 55°F at night; December is the coldest at 46°F and 34°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 45% of years.

Warmth for growing adds up to 1,765 growing degree days a year (base 50°F), fewer than at 69% of the 113 Washington stations. 30% of them (536) have built up by the end of June, and August adds the most, 431. Precipitation totals 34.8 inches a year, most in November (5.2") and least in July (0.9"); May to September bring 22% of it.

The nearest other station, Bellingham 3 SSW, WA, 11 miles southeast of Ferndale, has a last frost 1 day later (April 1), a first frost 3 days later (November 2), a season 5 days longer.

The first measurable snow (0.1 inch or more) in Ferndale 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, 15.3 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 31 days after the last snow.

ZIP 98248 is 6 miles from Bellingham International Airport, WA, which stands at 149 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 98248 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.