Frost Dates for 83801 — Athol, Idaho

Half of springs at Bayview Model Basin, ID see their last 32°F night by May 22; only one in ten is past it by May 5, and one in ten still has one after June 6. Planting tender crops after May 28 leaves a 30% risk of a frost on them, after May 31 20%, and after June 6 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 78% of the 67 Idaho stations behind this site's ZIP pages.

In fall the first 32°F night comes by September 22 in half of years, as early as September 3 one year in ten, and holds off past October 7 one year in ten. A hard freeze of 28°F follows 12 days later, around October 4; in spring the one-in-ten date for 28°F is May 23, 14 days before the 32°F one. The freeze-free season lasts 122 days in a typical year, shorter than at 76% of the 67 Idaho stations; it reaches 146 days one year in ten and falls short of 96 one year in ten. On average 172 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 June 7, and return around September 6. Severe cold of 16°F or below comes every winter, usually between November 18 and February 28.

July is the warmest month at Bayview Model Basin, ID, averaging 80°F by day and 50°F at night; December is the coldest at 34°F and 22°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 18% of years.

Warmth for growing adds up to 1,479 growing degree days a year (base 50°F), fewer than at 93% of the 67 Idaho stations. 25% of them (365) have built up by the end of June, and July adds the most, 464. Precipitation totals 24.7 inches a year, most in December (3.6") and least in July (0.9"); May to September bring 28% of it.

The nearest other station, Coeur D'Alene, ID, 19 miles south of Athol, has a last frost 30 days earlier (April 22), a first frost 26 days later (October 18), a season 57 days longer.

The first measurable snow (0.1 inch or more) in Athol usually arrives around November 28, and the last of the season around March 3. Those are the middle dates across the winters of 1991–2020 at Bayview Model Basin, ID, 5.5 miles away: half of years saw snow earlier, half later. Snow fell in 96% of those winters. The last 32°F night of spring typically comes 80 days after the last snow.

ZIP 83801 is 6 miles from Bayview Model Basin, ID, which stands at 2,087 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 83801 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.