Frost Dates for 98042 — Covington, Washington

Half of springs at Kent, WA see their last 32°F night by March 20; only one in ten is past it by February 27, and one in ten still has one after April 8. Planting tender crops after March 29 leaves a 30% risk of a frost on them, after April 1 20%, and after April 8 10%. The 19 days between the even-odds date and the one-in-ten date is narrower than at 49% of the 113 Washington stations behind this site's ZIP pages.

In fall the first 32°F night comes by November 10 in half of years, as early as October 26 one year in ten, and holds off past November 26 one year in ten. A hard freeze of 28°F follows 14 days later, around November 24; in spring the one-in-ten date for 28°F is March 16, 23 days before the 32°F one. The freeze-free season lasts 233 days in a typical year, longer than at 83% of the 113 Washington stations; it reaches 262 days one year in ten and falls short of 207 one year in ten. On average 39 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 22 days longer, to about April 11, and return around October 27. Nights of 24°F, cold enough to damage hardier plants, come in 88% of winters and 16°F in 11%.

July is the warmest month at Kent, WA, averaging 78°F by day and 57°F at night; December is the coldest at 47°F and 35°F. A freezing night is all but certain in every month from November to February (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, March still brings one in 84% of years and April still brings one in 22% of years.

Warmth for growing adds up to 2,408 growing degree days a year (base 50°F), more than at 71% of the 113 Washington stations. 32% of them (773) have built up by the end of June, and July adds the most, 552. Precipitation totals 40.3 inches a year, most in November (6.2") and least in July (0.7"); May to September bring 17% of it.

The nearest other station, Landsburg, WA, 7 miles east of Covington and 505 feet higher, has a last frost 31 days later (April 20), a first frost 16 days earlier (October 25), a season 46 days shorter.

Measurable snow is rare here: only 6 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Kent, WA, 7.1 miles away, so there is no typical first-snow date to plan around.

ZIP 98042 is 7 miles from Kent, WA, which stands at 30 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 5 other ZIP codes share the station; its figures are presented in full for 98092 (Auburn). The 2023 USDA Plant Hardiness Zone Map lists ZIP 98042 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.