Frost Dates for 98822 — Entiat, Washington

Half of springs at Entiat Fish Hatchery, WA see their last 32°F night by April 5; only one in ten is past it by March 17, and one in ten still has one after May 2. Planting tender crops after April 13 leaves a 30% risk of a frost on them, after April 21 20%, and after May 2 10%. The 27 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 24 in half of years, as early as September 29 one year in ten, and holds off past November 10 one year in ten. A hard freeze of 28°F follows 14 days later, around November 7; in spring the one-in-ten date for 28°F is April 4, 28 days before the 32°F one. The freeze-free season lasts 200 days in a typical year, longer than at 58% of the 113 Washington stations; it reaches 227 days one year in ten and falls short of 157 one year in ten. On average 134 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 12. Severe cold of 16°F or below comes in 96% of winters, usually between December 16 and February 2.

July is the warmest month at Entiat Fish Hatchery, WA, averaging 88°F by day and 58°F at night; January is the coldest at 35°F and 25°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 59% of years.

Warmth for growing adds up to 2,800 growing degree days a year (base 50°F), more than at 85% of the 113 Washington stations. 31% of them (857) have built up by the end of June, and July adds the most, 705. Precipitation totals 13.8 inches a year, most in December (2.4") and least in July (0.3"); May to September bring 20% of it.

The nearest other station, Plain, WA, 13 miles west of Entiat and 909 feet higher, has a last frost 47 days later (May 22), a first frost 32 days earlier (September 22), a season 79 days shorter.

The first measurable snow (0.1 inch or more) in Entiat usually arrives around November 26, and the last of the season around March 3. Those are the middle dates across the winters of 1991–2020 at Entiat Fish Hatchery, WA, 6 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 33 days after the last snow.

ZIP 98822 is 6 miles from Entiat Fish Hatchery, WA, which stands at 1,027 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 98822 in zone 7a, the band where the coldest night of the year averaged 0 to 5°F (-17.8 to -15.0°C) over 1991–2020; a zone describes winter lows, not frost dates.