USDA Hardiness Zone 5a
Frost Dates for 57793 — Whitewood, South Dakota
NOAA 1991–2020 normals from Deadwood, SD (4,670 ft), 9 miles southwest.
Updated
In Whitewood, the last spring frost (32°F) is around May 24 in half of years and has passed by June 6 in nine years out of ten. The first fall frost comes around September 25, as early as September 9 one year in ten, leaving a typical freeze-free season of 125 days (NOAA, Deadwood, SD).
- Last spring frost
- May 24
- First fall frost
- September 25
- Growing season
- 125 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
- October 4
- Last snow
- May 11
- Winters with snow
- 100%
- Snow per year
- 183.9"
median, 1991–2020
median, 1991–2020
30 of 30 observed
NOAA normal
Frost risk by date in Whitewood
Half of springs at Deadwood, SD see their last 32°F night by May 24; only one in ten is past it by May 7, and one in ten still has one after June 6. Planting tender crops after May 30 leaves a 30% risk of a frost on them, after June 2 20%, and after June 6 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 43% of the 49 South Dakota stations behind this site's ZIP pages.
In fall the first 32°F night comes by September 25 in half of years, as early as September 9 one year in ten, and holds off past October 9 one year in ten. A hard freeze of 28°F follows 8 days later, around October 3; in spring the one-in-ten date for 28°F is June 2, 4 days before the 32°F one. The freeze-free season lasts 125 days in a typical year, the shortest of the 49 South Dakota stations; it reaches 146 days one year in ten and falls short of 104 one year in ten. On average 192 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 7 days longer, to about May 31, and return around September 16. Severe cold of 16°F or below comes every winter, usually between November 1 and April 4.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 18 | May 23 | May 27 | May 29 | May 31 | Jun 3 | Jun 5 | Jun 9 | Jun 16 |
| 32°F | May 7 | May 13 | May 17 | May 21 | May 24 | May 27 | May 30 | Jun 2 | Jun 6 |
| 28°F | Apr 27 | May 1 | May 5 | May 9 | May 14 | May 17 | May 21 | May 26 | Jun 2 |
| 24°F | Apr 11 | Apr 17 | Apr 22 | Apr 27 | Apr 30 | May 3 | May 6 | May 13 | May 20 |
| 20°F | Mar 29 | Apr 4 | Apr 8 | Apr 11 | Apr 15 | Apr 19 | Apr 24 | Apr 29 | May 4 |
| 16°F | Mar 17 | Mar 24 | Mar 29 | Apr 1 | Apr 4 | Apr 8 | Apr 11 | Apr 15 | Apr 22 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 1 | Sep 5 | Sep 10 | Sep 13 | Sep 16 | Sep 19 | Sep 22 | Sep 25 | Sep 29 |
| 32°F | Sep 9 | Sep 14 | Sep 19 | Sep 22 | Sep 25 | Sep 28 | Oct 1 | Oct 4 | Oct 9 |
| 28°F | Sep 16 | Sep 23 | Sep 27 | Sep 30 | Oct 3 | Oct 6 | Oct 10 | Oct 14 | Oct 18 |
| 24°F | Sep 26 | Oct 2 | Oct 5 | Oct 9 | Oct 14 | Oct 16 | Oct 20 | Oct 23 | Oct 29 |
| 20°F | Oct 6 | Oct 13 | Oct 17 | Oct 21 | Oct 23 | Oct 26 | Oct 30 | Nov 2 | Nov 9 |
| 16°F | Oct 16 | Oct 22 | Oct 26 | Oct 29 | Nov 1 | Nov 5 | Nov 9 | Nov 13 | Nov 20 |
Freeze probabilities 1991–2020 at Deadwood, 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 57793 →Compare Whitewood with another place →
Weather by month in Whitewood
July is the warmest month at Deadwood, SD, averaging 83°F by day and 56°F at night; January is the coldest at 38°F and 14°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 24% of years.
Warmth for growing adds up to 2,035 growing degree days a year (base 50°F), fewer than at 96% of the 49 South Dakota stations. 27% of them (547) have built up by the end of June, and July adds the most, 600.
| Month | High °F | Low °F | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|
| Jan | 38 | 14 | 100% | 31 | 0 |
| Feb | 39 | 14 | 100% | 27 | 0 |
| Mar | 48 | 22 | 100% | 28 | 5 |
| Apr | 55 | 30 | 100% | 19 | 29 |
| May | 65 | 39 | 96% | 9 | 139 |
| Jun | 75 | 49 | 24% | <1 | 374 |
| Jul | 83 | 56 | 0% | 0 | 600 |
| Aug | 82 | 54 | 3% | <1 | 550 |
| Sep | 73 | 44 | 67% | 4 | 281 |
| Oct | 58 | 31 | 100% | 16 | 50 |
| Nov | 47 | 22 | 100% | 27 | 8 |
| Dec | 38 | 15 | 100% | 31 | 0 |
Monthly normals 1991–2020 at Deadwood, SD (4,670 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, Fort Meade, SD, 9 miles southeast of Whitewood and 1,362 feet lower, has a last frost 16 days earlier (May 8), a first frost 8 days later (October 3), a season 22 days longer.
When it snows in Whitewood, South Dakota
The first measurable snow (0.1 inch or more) in Whitewood usually arrives around October 4, and the last of the season around May 11. Those are the middle dates across the winters of 1991–2020 at Lead, SD, 9.9 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 13 days after the last snow.
Planting calendar for 57793
| When | What to do |
|---|---|
| March 15 – March 29 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 29 – April 12 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 26 – May 10 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 24 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 3 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 11 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| September 25 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 57793 is 9 miles from Deadwood, SD, which stands at 4,670 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 57793 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.