Frost Dates for 97913 — Nyssa, Oregon

Half of springs at Nyssa, OR see their last 32°F night by April 18; only one in ten is past it by March 30, and one in ten still has one after May 4. Planting tender crops after April 25 leaves a 30% risk of a frost on them, after April 28 20%, and after May 4 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 91% of the 103 Oregon stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 18 in half of years, as early as October 4 one year in ten, and holds off past November 1 one year in ten. A hard freeze of 28°F follows 10 days later, around October 28; in spring the one-in-ten date for 28°F is April 20, 14 days before the 32°F one. The freeze-free season lasts 182 days in a typical year, shorter than at 64% of the 103 Oregon stations; it reaches 204 days one year in ten and falls short of 160 one year in ten. On average 128 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 13 days longer, to about May 1, and return around October 6. Severe cold of 16°F or below comes in 98% of winters, usually between December 1 and February 4.

July is the warmest month at Nyssa, OR, averaging 91°F by day and 62°F at night; January is the coldest at 35°F and 24°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 87% of years and May still brings one in 13% of years.

Warmth for growing adds up to 3,050 growing degree days a year (base 50°F), more than at 91% of the 103 Oregon stations. 31% of them (947) have built up by the end of June, and July adds the most, 825. Precipitation totals 10.2 inches a year, most in January (1.4") and least in August (0.2"); May to September bring 28% of it.

The nearest other station, Parma Exp Stn, ID, 8 miles south of Nyssa, has a last frost 9 days later (April 27), a first frost 9 days earlier (October 9), a season 17 days shorter.

The first measurable snow (0.1 inch or more) in Nyssa usually arrives around December 6, and the last of the season around February 2. Those are the middle dates across the winters of 1991–2020 at Nyssa, OR, 2.5 miles away: half of years saw snow earlier, half later. Snow fell in 90% of those winters. The last 32°F night of spring typically comes 75 days after the last snow.

ZIP 97913 is 3 miles from Nyssa, OR, which stands at 2,175 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 97913 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.