Frost Dates for 71665 — Rison, Arkansas

Half of springs at Rison, AR see their last 32°F night by March 17; only one in ten is past it by February 26, and one in ten still has one after April 6. Planting tender crops after March 27 leaves a 30% risk of a frost on them, after April 1 20%, and after April 6 10%. The 20 days between the even-odds date and the one-in-ten date is wider than at 92% of the 105 Arkansas stations behind this site's ZIP pages.

In fall the first 32°F night comes by November 14 in half of years, as early as October 30 one year in ten, and holds off past December 4 one year in ten. A hard freeze of 28°F follows 14 days later, around November 28; in spring the one-in-ten date for 28°F is March 24, 13 days before the 32°F one. The freeze-free season lasts 241 days in a typical year, longer than at 88% of the 105 Arkansas stations; it reaches 269 days one year in ten and falls short of 214 one year in ten. On average 52 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 15 days longer, to about April 1, and return around November 2. Nights of 24°F, cold enough to damage hardier plants, come in 99% of winters and 16°F in 48%.

July is the warmest month at Rison, AR, averaging 91°F by day and 72°F at night; January is the coldest at 53°F and 34°F. A freezing night is all but certain in every month from December to February (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, March still brings one in 82% of years and April still brings one in 21% of years.

Warmth for growing adds up to 5,591 growing degree days a year (base 50°F), more than at 84% of the 105 Arkansas stations. 41% of them (2,270) have built up by the end of June, and July adds the most, 972.

The nearest other station, Fordyce, AR, 17 miles southwest of Rison, has a last frost 9 days later (March 26), a first frost 8 days earlier (November 6), a season 15 days shorter.

The first measurable snow (0.1 inch or more) in Rison usually arrives around January 22, and the last of the season around January 22. Those are the middle dates across the winters of 1991–2020 at Rison, AR, 3.3 miles away: half of years saw snow earlier, half later. Snow fell in 60% of those winters. The last 32°F night of spring typically comes 54 days after the last snow.

ZIP 71665 is 3 miles from Rison, AR, which stands at 280 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 71665 in zone 8a, the band where the coldest night of the year averaged 10 to 15°F (-12.2 to -9.4°C) over 1991–2020; a zone describes winter lows, not frost dates.