Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated

Planting zone for 57269 — Twin Brooks, SD

ZIP code 57269 (Twin Brooks, Grant County) is in USDA zone 4b: the coldest winter night averages −25 to −20 °F. The median last spring frost is May 2 and the first fall frost October 4.

Where ZIP 57269 is

Outlined: the ZIP code area · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone4b−25 to −20 °F
Coldest night−31.7 to −28.9 °C
Last frostMay 2
First frostOct 4
2012 zone4b

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 4b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Twin Brooks, SD…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in Twin Brooks, SD

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 2median — 50% chance of a later frost
Safe for tender plantsMay 15only 10% chance of frost after
First fall frostOctober 4median — 10% chance by Sep 22
Growing season153 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 24 and returns around October 12.

From the NOAA station Milbank 4 Nw, SD — 7 miles away, elevation 1,145 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in 57269

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 21 – Apr 4
SpinachSow outdoors · Mar 21 – Apr 11
Broccoli, cabbageStart indoors · Feb 21 – Mar 7
Broccoli, cabbageTransplant · Apr 11 – Apr 25
Onion setsPlant outdoors · Apr 4 – Apr 18
PotatoesPlant outdoors · Apr 11 – Apr 25
LettuceSow outdoors · Apr 4 – Apr 18
Carrots, beetsSow outdoors · Apr 11 – Apr 25
TomatoesStart indoors · Mar 7 – Mar 21
TomatoesTransplant · May 9 – May 23
Peppers, eggplantStart indoors · Feb 21 – Mar 7
Peppers, eggplantTransplant · May 16 – May 30
BeansSow outdoors · May 9 – May 23
Sweet cornSow outdoors · May 9 – May 23
Cucumbers, squashSow outdoors · May 9 – May 23
Fall lettuce, spinachSow outdoors · Aug 9 – Aug 23
GarlicPlant cloves · Sep 20 – Oct 25
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 2) and first fall frost (Oct 4) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 57269 came on Apr 12 — 7 days earlier than the 1991–2020 average (Apr 19).

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Native plants for zone 4b in South Dakota

430 plants native to the lower 48 states, recorded in South Dakota, and rated by the USDA to survive −25 °F or colder — the bottom of zone 4b. Each links to its USDA PLANTS profile.

Trees 23

American basswood100 ft · blooms late spring · low shade tolerance · to −46 °FAmerican elm120 ft · blooms early spring · medium shade tolerance · to −46 °Fbalsam poplar80 ft · blooms late spring · high shade tolerance · to −79 °Fblack locust60 ft · blooms spring · high shade tolerance · to −37 °Fblack maple100 ft · blooms late spring · low shade tolerance · to −47 °Fblack walnut100 ft · blooms late spring · high shade tolerance · to −28 °F

Shrubs 65

alderleaf buckthorn3 ft · blooms late spring · low shade tolerance · to −33 °Falderleaf mountain mahogany15 ft · blooms late spring · medium shade tolerance · to −41 °FAmerican black currant3 ft · blooms early spring · to −46 °FAmerican hazelnut10 ft · blooms spring · medium shade tolerance · to −33 °FAmerican plum24 ft · blooms mid spring · high shade tolerance · to −38 °Fbeaked hazelnut15 ft · blooms early spring · low shade tolerance · to −47 °F

Wildflowers & perennials 191

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine bistort1 ft · blooms mid spring · high shade tolerance · to −38 °Falpine mountainsorrel1 ft · blooms mid summer · medium shade tolerance · to −43 °Falpine sweetvetch2 ft · blooms early summer · high shade tolerance · to −62 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °FAmerican licorice4 ft · blooms late spring · medium shade tolerance · to −38 °F

Grasses 138

Alaska oniongrass3 ft · blooms mid spring · low shade tolerance · to −33 °Falkali cordgrass3 ft · blooms late summer · high shade tolerance · to −38 °Falkali sacaton3 ft · blooms mid summer · high shade tolerance · to −38 °Falpine timothy1.4 ft · blooms late spring · medium shade tolerance · to −43 °Farctic brome3 ft · blooms early summer · low shade tolerance · to −33 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °F

Vines 5

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °FVirginia creeper1 ft · blooms late spring · medium shade tolerance · to −28 °Fwestern white clematis1 ft · blooms mid summer · medium shade tolerance · to −38 °F

Source: USDA, NRCS. 2026. The PLANTS Database (plants.usda.gov), National Plant Data Team — state distribution, native status and the “Temperature, Minimum” characteristic. Check light, moisture and soil needs before buying; local nurseries and your state native plant society can confirm what thrives in Twin Brooks, SD.

Soil in Twin Brooks, SD

The soil mapped at the center of ZIP 57269 is Renshaw — loam, somewhat excessively drained.

TextureLoama good balance for most vegetables
pH7.0neutral; most vegetables like 6.0–7.0
DrainageSomewhat excessively drainednatural drainage class
Organic matter2.5%moderate
Hydrologic groupBwater soaks in moderately
Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Renshaw loam, 0 to 2 percent slopes.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 57269; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Twin Brooks, SD

Summer high84 °Faverage high, July
Winter low2 °Faverage low, January
Hot days16days a year at 90 °F or more
Freezing nights174nights a year at 32 °F or less
Growing degree days2,630base 50 °F — the season’s usable heat
Longest day15 h 39 mindaylight on June 21
Shortest day8 h 44 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation25.4 inper year, rain and melted snow

Average high and low, by month

−10°0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 22 °F, low 2 °F 22°2° JanFebruary: average high 27 °F, low 6 °F 27°6° FebMarch: average high 40 °F, low 19 °F 40°19° MarApril: average high 55 °F, low 32 °F 55°32° AprMay: average high 69 °F, low 46 °F 69°46° MayJune: average high 79 °F, low 57 °F 79°57° JunJuly: average high 84 °F, low 61 °F 84°61° JulAugust: average high 82 °F, low 59 °F 82°59° AugSeptember: average high 74 °F, low 49 °F 74°49° SepOctober: average high 59 °F, low 35 °F 59°35° OctNovember: average high 42 °F, low 21 °F 42°21° NovDecember: average high 27 °F, low 8 °F 27°8° Dec

Precipitation by month inches

0″1″2″3″4″January: 0.73 in precipitation 0.7 JanFebruary: 0.73 in precipitation 0.7 FebMarch: 1.22 in precipitation 1.2 MarApril: 2.49 in precipitation 2.5 AprMay: 2.96 in precipitation 3.0 MayJune: 3.92 in precipitation 3.9 JunJuly: 3.66 in precipitation 3.7 JulAugust: 3.00 in precipitation 3.0 AugSeptember: 2.59 in precipitation 2.6 SepOctober: 2.29 in precipitation 2.3 OctNovember: 1.01 in precipitation 1.0 NovDecember: 0.77 in precipitation 0.8 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Milbank 4 Nw, SD (7 mi away); precipitation: Milbank 0.9 Nnw, SD (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 4b.

572514b
Marvin, SD · 7 mi
572644b
Stockholm, SD · 8 mi
572524b
Milbank, SD · 9 mi
572274b
Corona, SD · 11 mi
572634b
South Shore, SD · 12 mi
572464b
Labolt, SD · 13 mi
572794b
Wilmot, SD · 14 mi
572164b
Big Stone City, SD · 14 mi

South Dakota planting zones →

Questions about 57269

What planting zone is ZIP code 57269?

ZIP code 57269 (Twin Brooks, SD) is in USDA hardiness zone 4b on the 2023 map: the coldest night of an average winter reaches −25 to −20 °F (−31.7 to −28.9 °C).

When is the last frost in Twin Brooks, SD?

The median last spring frost (32 °F) near 57269 is May 2; after May 15 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Milbank 4 Nw station.

When is the first frost in Twin Brooks, SD?

The median first fall frost near 57269 is October 4, giving a median frost-free growing season of 153 days.

When should I plant tomatoes in 57269?

Start tomato seeds indoors around Mar 7 – Mar 21 and set transplants outside around May 9 – May 23, one to three weeks after the median last frost.

How much rain and snow does 57269 get?

About 25.4 inches of precipitation a year (NOAA 1991–2020 normals, Milbank 0.9 Nnw station).

How hot do summers get in Twin Brooks, SD?

The average high peaks at 84 °F in July, with about 16 days a year at 90 °F or more.

What kind of soil does 57269 have?

The USDA soil survey maps Renshaw at the center of ZIP 57269: loam, somewhat excessively drained, pH about 7.0 (neutral).

Did spring come early in Twin Brooks, SD in 2026?

Spring leaf-out near 57269 came on Apr 12 in 2026, 7 days earlier than the 1991–2020 average (Apr 19), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Twin Brooks, SD?

Long-day onions: the longest day near 57269 is 15 h 39 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).