Frost Dates for 83661 — Payette, Idaho

Half of springs at Payette, ID see their last 32°F night by April 19; only one in ten is past it by April 1, and one in ten still has one after May 5. Planting tender crops after April 27 leaves a 30% risk of a frost on them, after April 30 20%, and after May 5 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 66% of the 67 Idaho stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 20 in half of years, as early as October 6 one year in ten, and holds off past November 4 one year in ten. A hard freeze of 28°F follows 11 days later, around October 31; in spring the one-in-ten date for 28°F is April 20, 15 days before the 32°F one. The freeze-free season lasts 183 days in a typical year, longer than at 96% of the 67 Idaho stations; it reaches 206 days one year in ten and falls short of 161 one year in ten. On average 131 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 2, and return around October 8. Severe cold of 16°F or below comes in 98% of winters, usually between December 5 and February 3.

July is the warmest month at Payette, ID, averaging 92°F by day and 61°F at night; January is the coldest at 39°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 88% of years and May still brings one in 20% of years.

Warmth for growing adds up to 3,204 growing degree days a year (base 50°F), more than at 94% of the 67 Idaho stations. 32% of them (1,014) have built up by the end of June, and July adds the most, 820. Precipitation totals 11.3 inches a year, most in December (1.8") and least in August (0.2"); May to September bring 32% of it.

The nearest other station, Ontario Ksrv, OR, 5 miles southwest of Payette, has a last frost 3 days later (April 22), a first frost 11 days earlier (October 9), a season 15 days shorter.

The first measurable snow (0.1 inch or more) in Payette usually arrives around December 15, and the last of the season around February 4. Those are the middle dates across the winters of 1991–2020 at Payette, ID, 1.8 miles away: half of years saw snow earlier, half later. Snow fell in 95% of those winters. The last 32°F night of spring typically comes 74 days after the last snow.

ZIP 83661 is 2 miles from Payette, ID, which stands at 2,150 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 83661 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.