Frost Dates for 97845 — John Day, Oregon

Half of springs at John Day, OR see their last 32°F night by May 28; only one in ten is past it by May 12, and one in ten still has one after June 15. Planting tender crops after June 4 leaves a 30% risk of a frost on them, after June 8 20%, and after June 15 10%. The 18 days between the even-odds date and the one-in-ten date is narrower than at 77% of the 103 Oregon stations behind this site's ZIP pages.

In fall the first 32°F night comes by September 18 in half of years, as early as September 2 one year in ten, and holds off past October 4 one year in ten. A hard freeze of 28°F follows 13 days later, around October 1; in spring the one-in-ten date for 28°F is May 24, 22 days before the 32°F one. The freeze-free season lasts 113 days in a typical year, shorter than at 90% of the 103 Oregon stations; it reaches 136 days one year in ten and falls short of 89 one year in ten. On average 163 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 22 days longer, to about June 19, and return around September 2. Severe cold of 16°F or below comes every winter, usually between November 14 and March 4.

July is the warmest month at John Day, OR, averaging 86°F by day and 48°F at night; December is the coldest at 39°F and 21°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, June still brings one in 39% of years.

Warmth for growing adds up to 1,760 growing degree days a year (base 50°F), fewer than at 74% of the 103 Oregon stations. 24% of them (424) have built up by the end of June, and July adds the most, 527. Precipitation totals 12.1 inches a year, most in May (1.8") and least in July (0.4"); May to September bring 37% of it.

The first measurable snow (0.1 inch or more) in John Day usually arrives around November 30, and the last of the season around March 10. Those are the middle dates across the winters of 1991–2020 at John Day, OR, 1.1 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 79 days after the last snow.

ZIP 97845 is 1 mile from John Day, OR, which stands at 3,063 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 97845 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.