Frost Dates for 57770 — Pine Ridge, South Dakota

Half of springs at Pine Ridge Airport, SD see their last 32°F night by May 16; only one in ten is past it by May 3, and one in ten still has one after May 31. Planting tender crops after May 22 leaves a 30% risk of a frost on them, after May 26 20%, and after May 31 10%. The 15 days between the even-odds date and the one-in-ten date is wider than at 84% of the 49 South Dakota stations behind this site's ZIP pages.

In fall the first 32°F night comes by September 27 in half of years, as early as September 13 one year in ten, and holds off past October 8 one year in ten. A hard freeze of 28°F follows 7 days later, around October 4; in spring the one-in-ten date for 28°F is May 19, 12 days before the 32°F one. The freeze-free season lasts 132 days in a typical year, shorter than at 94% of the 49 South Dakota stations; it reaches 151 days one year in ten and falls short of 110 one year in ten. On average 181 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 10 days longer, to about May 26, and return around September 17. Severe cold of 16°F or below comes every winter, usually between October 30 and April 2.

July is the warmest month at Pine Ridge Airport, SD, averaging 89°F by day and 60°F at night; January is the coldest at 37°F and 12°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month.

Warmth for growing adds up to 2,748 growing degree days a year (base 50°F), more than at 57% of the 49 South Dakota stations. 29% of them (806) have built up by the end of June, and July adds the most, 758. Precipitation totals 16.7 inches a year, most in June (3.0") and least in January (0.3"); May to September bring 64% of it.

The nearest other station, Oglala 1S, SD, 12 miles northwest of Pine Ridge and 283 feet lower, has a last frost 9 days earlier (May 7), a first frost 7 days later (October 4), a season 17 days longer.

The first measurable snow (0.1 inch or more) in Pine Ridge usually arrives around November 10, and the last of the season around April 23. Those are the middle dates across the winters of 1991–2020 at Oglala 1S, SD, 12.4 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 23 days after the last snow.

ZIP 57770 is 3 miles from Pine Ridge Airport, SD, which stands at 3,278 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 57770 in zone 5a, the band where the coldest night of the year averaged -20 to -15°F (-28.9 to -26.1°C) over 1991–2020; a zone describes winter lows, not frost dates.