USDA Hardiness Zone 4b
Frost Dates for 57469 — Redfield, South Dakota
NOAA 1991–2020 normals from Redfield, SD (1,309 ft), under a mile east.
Updated
In Redfield, 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 October 1, as early as September 19 one year in ten, leaving a typical freeze-free season of 145 days (NOAA, Redfield, SD).
- Last spring frost
- May 8
- First fall frost
- October 1
- Growing season
- 145 days
- Hardiness zone
- 4b
50% probability
50% probability
freeze-free, 50%
-25 to -20°F (-31.7 to -28.9°C) coldest night
- First snow
- November 10
- Last snow
- March 22
- Winters with snow
- 100%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
18 of 18 observed
NOAA normal
Frost risk by date in Redfield
Half of springs at Redfield, SD see their last 32°F night by May 8; only one in ten is past it by April 25, and one in ten still has one after May 21. Planting tender crops after May 13 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 October 1 in half of years, as early as September 19 one year in ten, and holds off past October 13 one year in ten. A hard freeze of 28°F follows 7 days later, around October 8; in spring the one-in-ten date for 28°F is May 12, 9 days before the 32°F one. The freeze-free season lasts 145 days in a typical year, shorter than at 67% of the 49 South Dakota stations; it reaches 162 days one year in ten and falls short of 128 one year in ten. On average 179 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 8 days longer, to about May 16, and return around September 23. Severe cold of 16°F or below comes every winter, usually between November 5 and April 3.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 5 | May 8 | May 11 | May 14 | May 16 | May 18 | May 21 | May 25 | May 29 |
| 32°F | Apr 25 | Apr 30 | May 2 | May 5 | May 8 | May 10 | May 13 | May 16 | May 21 |
| 28°F | Apr 14 | Apr 19 | Apr 23 | Apr 26 | Apr 29 | May 1 | May 4 | May 7 | May 12 |
| 24°F | Apr 5 | Apr 9 | Apr 12 | Apr 16 | Apr 19 | Apr 22 | Apr 25 | Apr 30 | May 4 |
| 20°F | Mar 27 | Apr 2 | Apr 5 | Apr 8 | Apr 10 | Apr 13 | Apr 16 | Apr 20 | Apr 26 |
| 16°F | Mar 15 | Mar 22 | Mar 28 | Mar 31 | Apr 3 | Apr 5 | Apr 7 | Apr 11 | Apr 16 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 10 | Sep 16 | Sep 19 | Sep 21 | Sep 23 | Sep 25 | Sep 28 | Oct 1 | Oct 4 |
| 32°F | Sep 19 | Sep 22 | Sep 26 | Sep 28 | Oct 1 | Oct 3 | Oct 5 | Oct 8 | Oct 13 |
| 28°F | Sep 25 | Sep 30 | Oct 2 | Oct 5 | Oct 8 | Oct 11 | Oct 14 | Oct 18 | Oct 22 |
| 24°F | Oct 2 | Oct 7 | Oct 11 | Oct 15 | Oct 18 | Oct 21 | Oct 23 | Oct 26 | Oct 30 |
| 20°F | Oct 13 | Oct 17 | Oct 22 | Oct 25 | Oct 28 | Oct 31 | Nov 2 | Nov 5 | Nov 10 |
| 16°F | Oct 22 | Oct 28 | Nov 1 | Nov 3 | Nov 5 | Nov 8 | Nov 11 | Nov 14 | Nov 19 |
Freeze probabilities 1991–2020 at Redfield, 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 57469 →Compare Redfield with another place →
Weather by month in Redfield
July is the warmest month at Redfield, SD, averaging 84°F by day and 60°F at night; January is the coldest at 23°F and 3°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 77% of years.
Warmth for growing adds up to 2,534 growing degree days a year (base 50°F), fewer than at 69% of the 49 South Dakota stations. 32% of them (808) have built up by the end of June, and July adds the most, 688. Precipitation totals 22.9 inches a year, most in June (4.1") and least in January (0.5"); May to September bring 67% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 23 | 3 | 0.5 | 100% | 31 | 0 |
| Feb | 28 | 7 | 0.6 | 100% | 28 | 0 |
| Mar | 41 | 20 | 0.9 | 100% | 27 | 4 |
| Apr | 56 | 32 | 2.1 | 100% | 16 | 48 |
| May | 69 | 44 | 3.3 | 77% | 3 | 243 |
| Jun | 79 | 56 | 4.1 | 0% | 0 | 513 |
| Jul | 84 | 60 | 3.3 | 0% | 0 | 688 |
| Aug | 82 | 57 | 2.7 | 0% | 0 | 615 |
| Sep | 74 | 48 | 2.0 | 50% | 2 | 345 |
| Oct | 59 | 34 | 2.0 | 100% | 14 | 74 |
| Nov | 42 | 21 | 0.7 | 100% | 28 | 4 |
| Dec | 28 | 9 | 0.7 | 100% | 31 | 0 |
Monthly normals 1991–2020 at Redfield, SD (1,309 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, Huron Regional Airport, SD, 36 miles southeast of Redfield, has a last frost 2 days earlier (May 6), a first frost 1 day later (October 2), a season 1 day longer.
When it snows in Redfield, South Dakota
The first measurable snow (0.1 inch or more) in Redfield usually arrives around November 10, and the last of the season around March 22. Those are the middle dates across the winters of 1991–2020 at Redfield, SD, 0.8 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 47 days after the last snow.
Planting calendar for 57469
| 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 9 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 17 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 1 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 57469 is under a mile from Redfield, SD, which stands at 1,309 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 57469 in zone 4b, the band where the coldest night of the year averaged -25 to -20°F (-31.7 to -28.9°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.