USDA Hardiness Zone 5a
Frost Dates for 57366 — Parkston, South Dakota
NOAA 1991–2020 normals from Alexandria, SD (1,365 ft), 19 miles northeast.
Updated
In Parkston, the last spring frost (32°F) is around May 8 in half of years and has passed by May 21 in nine years out of ten. The first fall frost comes around September 29, as early as September 17 one year in ten, leaving a typical freeze-free season of 143 days (NOAA, Alexandria, SD).
- Last spring frost
- May 8
- First fall frost
- September 29
- Growing season
- 143 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 19
- Last snow
- April 13
- Winters with snow
- 96%
- Snow per year
- 36.3"
median, 1991–2020
median, 1991–2020
27 of 28 observed
NOAA normal
Frost risk by date in Parkston
Half of springs at Alexandria, SD see their last 32°F night by May 8; only one in ten is past it by April 27, and one in ten still has one after May 21. Planting tender crops after May 14 leaves a 30% risk of a frost on them, after May 16 20%, and after May 21 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 29 in half of years, as early as September 17 one year in ten, and holds off past October 11 one year in ten. A hard freeze of 28°F follows 8 days later, around October 7; in spring the one-in-ten date for 28°F is May 13, 8 days before the 32°F one. The freeze-free season lasts 143 days in a typical year, shorter than at 76% of the 49 South Dakota stations; it reaches 160 days one year in ten and falls short of 126 one year in ten. On average 159 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 18, and return around September 22. Severe cold of 16°F or below comes every winter, usually between November 3 and April 2.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 5 | May 9 | May 13 | May 15 | May 18 | May 20 | May 23 | May 27 | May 31 |
| 32°F | Apr 27 | Apr 30 | May 3 | May 5 | May 8 | May 10 | May 14 | May 16 | May 21 |
| 28°F | Apr 15 | Apr 21 | Apr 25 | Apr 29 | Apr 30 | May 3 | May 5 | May 8 | May 13 |
| 24°F | Apr 6 | Apr 10 | Apr 14 | Apr 17 | Apr 21 | Apr 24 | Apr 27 | Apr 30 | May 4 |
| 20°F | Mar 26 | Apr 1 | Apr 4 | Apr 7 | Apr 10 | Apr 13 | Apr 17 | Apr 21 | Apr 27 |
| 16°F | Mar 14 | Mar 20 | Mar 26 | Mar 30 | Apr 2 | Apr 4 | Apr 8 | Apr 11 | Apr 18 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 9 | Sep 13 | Sep 16 | Sep 19 | Sep 22 | Sep 24 | Sep 27 | Sep 29 | Oct 2 |
| 32°F | Sep 17 | Sep 21 | Sep 24 | Sep 27 | Sep 29 | Oct 1 | Oct 3 | Oct 7 | Oct 11 |
| 28°F | Sep 24 | Sep 29 | Oct 2 | Oct 4 | Oct 7 | Oct 10 | Oct 13 | Oct 16 | Oct 20 |
| 24°F | Oct 2 | Oct 6 | Oct 10 | Oct 14 | Oct 17 | Oct 20 | Oct 23 | Oct 26 | Oct 30 |
| 20°F | Oct 12 | Oct 17 | Oct 21 | Oct 23 | Oct 25 | Oct 28 | Oct 31 | Nov 3 | Nov 7 |
| 16°F | Oct 22 | Oct 26 | Oct 30 | Nov 1 | Nov 3 | Nov 5 | Nov 8 | Nov 13 | Nov 18 |
Freeze probabilities 1991–2020 at Alexandria, 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 57366 →Compare Parkston with another place →
Weather by month in Parkston
July is the warmest month at Alexandria, SD, averaging 84°F by day and 60°F at night; January is the coldest at 25°F and 6°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 79% of years.
Warmth for growing adds up to 2,614 growing degree days a year (base 50°F), fewer than at 61% of the 49 South Dakota stations. 33% of them (852) have built up by the end of June, and July adds the most, 685. Precipitation totals 25.2 inches a year, most in June (4.0") and least in January (0.5"); May to September bring 65% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 25 | 6 | 0.5 | 100% | 31 | 0 |
| Feb | 31 | 10 | 0.7 | 100% | 27 | 1 |
| Mar | 44 | 21 | 1.1 | 100% | 24 | 13 |
| Apr | 58 | 32 | 2.9 | 100% | 12 | 62 |
| May | 69 | 44 | 3.6 | 79% | 1 | 253 |
| Jun | 79 | 56 | 4.0 | 1% | 0 | 524 |
| Jul | 84 | 60 | 3.1 | 0% | 0 | 685 |
| Aug | 82 | 57 | 3.0 | 0% | 0 | 608 |
| Sep | 75 | 49 | 2.8 | 55% | <1 | 367 |
| Oct | 60 | 35 | 2.0 | 100% | 9 | 94 |
| Nov | 43 | 21 | 0.9 | 100% | 24 | 8 |
| Dec | 29 | 10 | 0.6 | 100% | 31 | 0 |
Monthly normals 1991–2020 at Alexandria, SD (1,365 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, Menno, SD, 22 miles southeast of Parkston, has a last frost 7 days earlier (May 1), a first frost 5 days later (October 4), a season 13 days longer.
When it snows in Parkston, South Dakota
The first measurable snow (0.1 inch or more) in Parkston usually arrives around November 19, and the last of the season around April 13. Those are the middle dates across the winters of 1991–2020 at Alexandria, SD, 19.4 miles away: half of years saw snow earlier, half later. Snow fell in 96% of those winters. The last 32°F night of spring typically comes 25 days after the last snow.
Planting calendar for 57366
| When | What to do |
|---|---|
| February 27 – March 13 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 13 – March 27 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 10 – April 24 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 8 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 7 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 15 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| September 29 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 57366 is 19 miles from Alexandria, SD, which stands at 1,365 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 57366 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.