USDA Hardiness Zone 5a
Frost Dates for 57580 — Winner, South Dakota
NOAA 1991–2020 normals from Winner, SD (2,016 ft), 9 miles northeast.
Updated
In Winner, the last spring frost (32°F) is around May 1 in half of years and has passed by May 16 in nine years out of ten. The first fall frost comes around October 9, as early as September 25 one year in ten, leaving a typical freeze-free season of 159 days (NOAA, Winner, SD).
- Last spring frost
- May 1
- First fall frost
- October 9
- Growing season
- 159 days
- Hardiness zone
- 5a
50% probability
50% probability
freeze-free, 50%
-20 to -15°F (-28.9 to -26.1°C) coldest night
- First snow
- November 5
- Last snow
- April 11
- Winters with snow
- 100%
- Snow per year
- 49.1"
median, 1991–2020
median, 1991–2020
28 of 28 observed
NOAA normal
Frost risk by date in Winner
Half of springs at Winner, SD see their last 32°F night by May 1; only one in ten is past it by April 17, and one in ten still has one after May 16. Planting tender crops after May 7 leaves a 30% risk of a frost on them, after May 11 20%, and after May 16 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 October 9 in half of years, as early as September 25 one year in ten, and holds off past October 23 one year in ten. A hard freeze of 28°F follows 9 days later, around October 18; in spring the one-in-ten date for 28°F is May 7, 9 days before the 32°F one. The freeze-free season lasts 159 days in a typical year, longer than at 86% of the 49 South Dakota stations; it reaches 178 days one year in ten and falls short of 139 one year in ten. On average 149 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 11, and return around October 1. Severe cold of 16°F or below comes every winter, usually between November 13 and March 27.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 27 | May 2 | May 4 | May 7 | May 11 | May 14 | May 17 | May 20 | May 25 |
| 32°F | Apr 17 | Apr 22 | Apr 26 | Apr 30 | May 1 | May 4 | May 7 | May 11 | May 16 |
| 28°F | Apr 7 | Apr 12 | Apr 16 | Apr 19 | Apr 22 | Apr 25 | Apr 29 | May 2 | May 7 |
| 24°F | Mar 28 | Apr 2 | Apr 5 | Apr 8 | Apr 12 | Apr 15 | Apr 18 | Apr 23 | Apr 27 |
| 20°F | Mar 16 | Mar 23 | Mar 28 | Mar 31 | Apr 3 | Apr 6 | Apr 9 | Apr 13 | Apr 19 |
| 16°F | Mar 7 | Mar 13 | Mar 18 | Mar 23 | Mar 27 | Mar 30 | Apr 2 | Apr 5 | Apr 12 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 18 | Sep 22 | Sep 26 | Sep 28 | Oct 1 | Oct 3 | Oct 6 | Oct 9 | Oct 14 |
| 32°F | Sep 25 | Sep 30 | Oct 2 | Oct 6 | Oct 9 | Oct 12 | Oct 15 | Oct 18 | Oct 23 |
| 28°F | Oct 2 | Oct 7 | Oct 11 | Oct 15 | Oct 18 | Oct 21 | Oct 24 | Oct 29 | Nov 1 |
| 24°F | Oct 11 | Oct 16 | Oct 21 | Oct 25 | Oct 28 | Oct 31 | Nov 3 | Nov 7 | Nov 12 |
| 20°F | Oct 20 | Oct 26 | Oct 30 | Nov 2 | Nov 5 | Nov 8 | Nov 12 | Nov 15 | Nov 21 |
| 16°F | Oct 29 | Nov 2 | Nov 6 | Nov 10 | Nov 13 | Nov 16 | Nov 20 | Nov 24 | Nov 28 |
Freeze probabilities 1991–2020 at Winner, SD, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 57580 →Compare Winner with another place →
Weather by month in Winner
July is the warmest month at Winner, SD, averaging 90°F by day and 63°F at night; January is the coldest at 35°F and 13°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 55% of years.
Warmth for growing adds up to 3,247 growing degree days a year (base 50°F), more than at 98% of the 49 South Dakota stations. 31% of them (1,017) have built up by the end of June, and July adds the most, 817. Precipitation totals 23.0 inches a year, most in June (3.9") and least in January (0.5"); May to September bring 64% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 35 | 13 | 0.5 | 100% | 29 | 1 |
| Feb | 39 | 15 | 0.6 | 100% | 25 | 4 |
| Mar | 50 | 24 | 1.1 | 100% | 23 | 28 |
| Apr | 61 | 35 | 2.8 | 100% | 11 | 92 |
| May | 72 | 47 | 3.6 | 55% | 2 | 308 |
| Jun | 82 | 57 | 3.9 | 0% | 0 | 584 |
| Jul | 90 | 63 | 2.6 | 0% | 0 | 817 |
| Aug | 87 | 61 | 2.4 | 0% | 0 | 749 |
| Sep | 80 | 52 | 2.2 | 23% | <1 | 478 |
| Oct | 65 | 38 | 1.8 | 97% | 7 | 159 |
| Nov | 50 | 26 | 0.8 | 100% | 22 | 26 |
| Dec | 37 | 16 | 0.7 | 100% | 29 | 1 |
Monthly normals 1991–2020 at Winner, SD (2,016 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
Compared with the next station
The nearest other station, Mission, SD, 34 miles west of Winner and 571 feet higher, has a last frost 8 days later (May 9), a first frost 8 days earlier (October 1), a season 13 days shorter.
When it snows in Winner, South Dakota
The first measurable snow (0.1 inch or more) in Winner usually arrives around November 5, and the last of the season around April 11. Those are the middle dates across the winters of 1991–2020 at Winner, SD, 8.6 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 20 days after the last snow.
Planting calendar for 57580
| When | What to do |
|---|---|
| February 20 – March 6 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 6 – March 20 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 3 – April 17 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 1 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 17 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 25 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 9 onward | Plant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter. |
The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.
Where these figures come from
ZIP 57580 is 9 miles from Winner, SD, which stands at 2,016 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 57580 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.
Frost dates across South Dakota →
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.