Frost Dates for 98513 — Olympia, Washington

Half of springs at Olympia Airport, WA see their last 32°F night by April 29; only one in ten is past it by April 11, and one in ten still has one after May 15. Planting tender crops after May 5 leaves a 30% risk of a frost on them, after May 9 20%, and after May 15 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 74% of the 113 Washington stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 14 in half of years, as early as September 28 one year in ten, and holds off past November 1 one year in ten. A hard freeze of 28°F follows 18 days later, around November 1; in spring the one-in-ten date for 28°F is April 29, 16 days before the 32°F one. The freeze-free season lasts 169 days in a typical year, shorter than at 69% of the 113 Washington stations; it reaches 195 days one year in ten and falls short of 144 one year in ten. On average 77 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 16 days longer, to about May 15, and return around September 28. Nights of 24°F, cold enough to damage hardier plants, come in 100% of winters and 16°F in 68%.

August is the warmest month at Olympia Airport, WA, averaging 78°F by day and 51°F at night; December is the coldest at 45°F and 33°F. A freezing night is all but certain in every month from November 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 44% of years.

Warmth for growing adds up to 1,723 growing degree days a year (base 50°F), fewer than at 76% of the 113 Washington stations. 28% of them (483) have built up by the end of June, and August adds the most, 442. Precipitation totals 50.8 inches a year, most in November (8.2") and least in July (0.5"); May to September bring 14% of it.

The nearest other station, Tacoma Narrows Airport, WA, 20 miles northeast of Olympia, has a last frost 49 days earlier (March 11), a first frost 38 days later (November 21), a season 85 days longer.

Measurable snow is rare here: only 5 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Centralia, WA, 21.9 miles away, so there is no typical first-snow date to plan around.

ZIP 98513 is 7 miles from Olympia Airport, WA, which stands at 188 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 9 other ZIP codes share the station; its figures are presented in full for 98501 (Olympia). The 2023 USDA Plant Hardiness Zone Map lists ZIP 98513 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.