USDA Hardiness Zone 5a
Frost Dates for 57301 — Mitchell, South Dakota
NOAA 1991–2020 normals from Mitchell 2 N, SD (1,250 ft), 2 miles north.
Updated
In Mitchell, the last spring frost (32°F) is around May 2 in half of years and has passed by May 15 in nine years out of ten. The first fall frost comes around October 6, as early as September 23 one year in ten, leaving a typical freeze-free season of 156 days (NOAA, Mitchell 2 N, SD).
- Last spring frost
- May 2
- First fall frost
- October 6
- Growing season
- 156 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 6
- Last snow
- April 10
- Winters with snow
- 100%
- Snow per year
- 40.6"
median, 1991–2020
median, 1991–2020
17 of 17 observed
NOAA normal
Frost risk by date in Mitchell
Half of springs at Mitchell 2 N, SD see their last 32°F night by May 2; only one in ten is past it by April 19, and one in ten still has one after May 15. Planting tender crops after May 6 leaves a 30% risk of a frost on them, after May 10 20%, and after May 15 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 October 6 in half of years, as early as September 23 one year in ten, and holds off past October 19 one year in ten. A hard freeze of 28°F follows 10 days later, around October 16; in spring the one-in-ten date for 28°F is May 4, 11 days before the 32°F one. The freeze-free season lasts 156 days in a typical year, longer than at 71% of the 49 South Dakota stations; it reaches 174 days one year in ten and falls short of 138 one year in ten. On average 168 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 9 days longer, to about May 11, and return around September 27. Severe cold of 16°F or below comes every winter, usually between November 10 and March 26.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 30 | May 3 | May 6 | May 8 | May 11 | May 13 | May 16 | May 19 | May 25 |
| 32°F | Apr 19 | Apr 24 | Apr 27 | Apr 30 | May 2 | May 4 | May 6 | May 10 | May 15 |
| 28°F | Apr 9 | Apr 13 | Apr 16 | Apr 19 | Apr 21 | Apr 24 | Apr 27 | Apr 30 | May 4 |
| 24°F | Apr 1 | Apr 4 | Apr 8 | Apr 10 | Apr 12 | Apr 15 | Apr 18 | Apr 21 | Apr 25 |
| 20°F | Mar 19 | Mar 25 | Mar 30 | Apr 2 | Apr 4 | Apr 7 | Apr 9 | Apr 13 | Apr 18 |
| 16°F | Mar 9 | Mar 15 | Mar 19 | Mar 22 | Mar 26 | Mar 30 | Apr 1 | Apr 5 | Apr 9 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 15 | Sep 19 | Sep 22 | Sep 25 | Sep 27 | Sep 30 | Oct 2 | Oct 5 | Oct 10 |
| 32°F | Sep 23 | Sep 27 | Sep 30 | Oct 3 | Oct 6 | Oct 9 | Oct 11 | Oct 14 | Oct 19 |
| 28°F | Sep 30 | Oct 5 | Oct 10 | Oct 13 | Oct 16 | Oct 18 | Oct 21 | Oct 24 | Oct 28 |
| 24°F | Oct 11 | Oct 17 | Oct 20 | Oct 23 | Oct 25 | Oct 28 | Oct 30 | Nov 2 | Nov 6 |
| 20°F | Oct 22 | Oct 26 | Oct 29 | Nov 1 | Nov 3 | Nov 5 | Nov 8 | Nov 11 | Nov 16 |
| 16°F | Oct 29 | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 13 | Nov 16 | Nov 19 | Nov 24 |
Freeze probabilities 1991–2020 at Mitchell 2 N, 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 57301 →Compare Mitchell with another place →
Frost risk through the year in Mitchell
In Mitchell, the spring curve drops under 10% on May 15 and the fall curve passes 10% on September 23, 131 days later; that gap is longer than at 73% of the 49 South Dakota stations with frost dates. The spring risk falls from 90% to 10% over 26 days (April 19 to May 15) and the fall risk climbs from 10% to 90% over 26 days (September 23 to October 19): both ends of the season vary about as much. At Alexandria, SD, 12 miles east, the same gap runs from May 21 to September 17, 12 days shorter.
| Planted on | Another 32°F night | 28°F night |
|---|---|---|
| Apr 18 | over 90% | 63% |
| Apr 25 | 77% | 37% |
| May 250% date | 50% | 15% |
| May 9 | 23% | under 10% |
| May 16 | under 10% | under 10% |
| May 23 | under 10% | under 10% |
Weather by month in Mitchell
July is the warmest month at Mitchell 2 N, SD, averaging 86°F by day and 62°F at night; January is the coldest at 28°F and 7°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 56% of years.
Warmth for growing adds up to 2,867 growing degree days a year (base 50°F), more than at 71% of the 49 South Dakota stations. 33% of them (937) have built up by the end of June, and July adds the most, 734.
| Month | High °F | Low °F | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|
| Jan | 28 | 7 | 100% | 31 | 0 |
| Feb | 33 | 11 | 100% | 27 | 1 |
| Mar | 45 | 22 | 100% | 26 | 11 |
| Apr | 58 | 34 | 100% | 13 | 63 |
| May | 70 | 47 | 56% | 1 | 287 |
| Jun | 81 | 58 | 0% | 0 | 576 |
| Jul | 86 | 62 | 0% | 0 | 734 |
| Aug | 84 | 60 | 0% | 0 | 677 |
| Sep | 77 | 50 | 32% | 1 | 406 |
| Oct | 62 | 36 | 100% | 11 | 101 |
| Nov | 45 | 22 | 100% | 27 | 12 |
| Dec | 32 | 12 | 100% | 31 | 0 |
Monthly normals 1991–2020 at Mitchell 2 N, SD (1,250 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, Alexandria, SD, 12 miles east of Mitchell, has a last frost 6 days later (May 8), a first frost 7 days earlier (September 29), a season 13 days shorter.
When it snows in Mitchell, South Dakota
The first measurable snow (0.1 inch or more) in Mitchell usually arrives around November 6, and the last of the season around April 10. Those are the middle dates across the winters of 1991–2020 at Mitchell, SD, 4.1 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 22 days after the last snow.
Planting calendar for 57301
| When | What to do |
|---|---|
| February 21 – March 7 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 7 – March 21 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 4 – April 18 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 2 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 14 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 22 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 6 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 57301 is 2 miles from Mitchell 2 N, SD, which stands at 1,250 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 57301 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.