Frost Dates for 98922 — Cle Elum, Washington

Half of springs at Cle Elum, WA see their last 32°F night by May 13; only one in ten is past it by April 29, and one in ten still has one after June 1. Planting tender crops after May 20 leaves a 30% risk of a frost on them, after May 26 20%, and after June 1 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 September 25 in half of years, as early as September 11 one year in ten, and holds off past October 7 one year in ten. A hard freeze of 28°F follows 10 days later, around October 5; in spring the one-in-ten date for 28°F is May 14, 18 days before the 32°F one. The freeze-free season lasts 132 days in a typical year, shorter than at 92% of the 113 Washington stations; it reaches 152 days one year in ten and falls short of 110 one year in ten. On average 156 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 June 1, and return around September 11. Severe cold of 16°F or below comes every winter, usually between November 24 and February 24.

July is the warmest month at Cle Elum, WA, averaging 81°F by day and 53°F at night; December is the coldest at 34°F and 22°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 82% of years and June still brings one in 11% of years.

Warmth for growing adds up to 1,759 growing degree days a year (base 50°F), fewer than at 71% of the 113 Washington stations. 26% of them (450) have built up by the end of June, and July adds the most, 524.

The nearest other station, Ellensburg Bowers Field, WA, 21 miles southeast of Cle Elum, has a last frost 15 days earlier (April 28), a first frost 12 days later (October 7), a season 31 days longer.

The first measurable snow (0.1 inch or more) in Cle Elum usually arrives around November 14, and the last of the season around March 29. Those are the middle dates across the winters of 1991–2020 at Cle Elum, WA, 0.4 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 45 days after the last snow.

ZIP 98922 is under a mile from Cle Elum, WA, which stands at 1,900 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 98922 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.