Frost Dates for 83336 — Heyburn, Idaho

Half of springs at Burley Municipal Airport, ID see their last 32°F night by May 7; only one in ten is past it by April 23, and one in ten still has one after May 23. Planting tender crops after May 12 leaves a 30% risk of a frost on them, after May 15 20%, and after May 23 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 4 in half of years, as early as September 21 one year in ten, and holds off past October 18 one year in ten. A hard freeze of 28°F follows 13 days later, around October 17; in spring the one-in-ten date for 28°F is May 5, 18 days before the 32°F one. The freeze-free season lasts 150 days in a typical year, longer than at 55% of the 67 Idaho stations; it reaches 169 days one year in ten and falls short of 129 one year in ten. On average 146 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 17 days longer, to about May 24, and return around September 21. Severe cold of 16°F or below comes every winter, usually between November 21 and February 25.

July is the warmest month at Burley Municipal Airport, ID, averaging 88°F by day and 55°F at night; December is the coldest at 37°F and 21°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 70% of years.

Warmth for growing adds up to 2,381 growing degree days a year (base 50°F), more than at 58% of the 67 Idaho stations. 28% of them (672) have built up by the end of June, and July adds the most, 666. Precipitation totals 10.5 inches a year, most in May (1.7") and least in July (0.3"); May to September bring 37% of it.

The nearest other station, Paul 1ENE, ID, 4 miles north of Heyburn, has a last frost 1 day earlier (May 6), a first frost 2 days later (October 6), a season 1 day longer.

The first measurable snow (0.1 inch or more) in Heyburn usually arrives around November 30, and the last of the season around March 13. Those are the middle dates across the winters of 1991–2020 at Paul 1ENE, ID, 3.6 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 55 days after the last snow.

ZIP 83336 is 2 miles from Burley Municipal Airport, ID, which stands at 4,142 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station; its figures are presented in full for 83318 (Burley). The 2023 USDA Plant Hardiness Zone Map lists ZIP 83336 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.