Frost Dates for 98847 — Peshastin, Washington

Half of springs at Leavenworth 3 S, WA see their last 32°F night by May 10; only one in ten is past it by April 27, and one in ten still has one after May 28. Planting tender crops after May 17 leaves a 30% risk of a frost on them, after May 21 20%, and after May 28 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 September 30 in half of years, as early as September 18 one year in ten, and holds off past October 14 one year in ten. A hard freeze of 28°F follows 13 days later, around October 13; in spring the one-in-ten date for 28°F is May 9, 19 days before the 32°F one. The freeze-free season lasts 142 days in a typical year, shorter than at 89% of the 113 Washington stations; it reaches 162 days one year in ten and falls short of 123 one year in ten. On average 160 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 21 days longer, to about May 31, and return around September 18. Severe cold of 16°F or below comes every winter, usually between November 25 and February 27.

July is the warmest month at Leavenworth 3 S, WA, averaging 87°F by day and 51°F at night; January is the coldest at 34°F and 19°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 77% of years.

Warmth for growing adds up to 2,094 growing degree days a year (base 50°F), more than at 58% of the 113 Washington stations. 27% of them (576) have built up by the end of June, and July adds the most, 589. Precipitation totals 25.8 inches a year, most in December (4.5") and least in August (0.4"); May to September bring 16% of it.

The nearest other station, Plain, WA, 16 miles north of Peshastin and 808 feet higher, has a last frost 12 days later (May 22), a first frost 8 days earlier (September 22), a season 21 days shorter.

The first measurable snow (0.1 inch or more) in Peshastin usually arrives around November 19, and the last of the season around March 9. Those are the middle dates across the winters of 1991–2020 at Leavenworth 3 S, WA, 3.3 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 62 days after the last snow.

ZIP 98847 is 3 miles from Leavenworth 3 S, WA, which stands at 1,128 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station; its figures are presented in full for 98815 (Cashmere). The 2023 USDA Plant Hardiness Zone Map lists ZIP 98847 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.