Frost Dates for 97846 — Joseph, Oregon

Half of springs at Joseph, OR see their last 32°F night by May 24; only one in ten is past it by May 6, and one in ten still has one after July 6. Planting tender crops after June 7 leaves a 30% risk of a frost on them, after June 18 20%, and after July 6 10%. The 43 days between the even-odds date and the one-in-ten date is wider than at 99% of the 103 Oregon 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 1 in half of years, as early as September 10 one year in ten, and holds off past October 15 one year in ten. A hard freeze of 28°F follows 12 days later, around October 13; in spring the one-in-ten date for 28°F is May 26, 41 days before the 32°F one. The freeze-free season lasts 126 days in a typical year, shorter than at 87% of the 103 Oregon stations; it reaches 152 days one year in ten and falls short of 82 one year in ten. On average 187 nights a year drop to 32°F or below. Severe cold of 16°F or below comes every winter, usually between November 15 and March 12.

August is the warmest month at Joseph, OR, averaging 80°F by day and 49°F at night; December is the coldest at 35°F and 18°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). August is the only month with under a 10% chance of a 32°F night. In spring, June still brings one in 30% of years and July still brings one in 14% of years.

Warmth for growing adds up to 1,511 growing degree days a year (base 50°F), fewer than at 88% of the 103 Oregon stations. 22% of them (328) have built up by the end of June, and August adds the most, 453. Precipitation totals 17.0 inches a year, most in May (2.6") and least in August (0.7"); May to September bring 42% of it.

The nearest other station, Enterprise 20 NNE, OR, 26 miles north of Joseph and 904 feet lower, has a last frost 15 days later (June 8), a first frost 26 days earlier (September 5), a season 42 days shorter.

The first measurable snow (0.1 inch or more) in Joseph usually arrives around November 6, and the last of the season around April 28. Those are the middle dates across the winters of 1991–2020 at Joseph, OR, 2.4 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 26 days after the last snow.

ZIP 97846 is 2 miles from Joseph, OR, which stands at 4,184 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 97846 in zone 6a, the band where the coldest night of the year averaged -10 to -5°F (-23.3 to -20.6°C) over 1991–2020; a zone describes winter lows, not frost dates.