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

Planting zone for 57642 — Mc Laughlin, SD

ZIP code 57642 (Mc Laughlin, Corson County) is in USDA zone 4b: the coldest winter night averages −25 to −20 °F. The median last spring frost is May 12 and the first fall frost September 28.

Where ZIP 57642 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 12
First frostSep 28
2012 zone4a

Was 4a on the 2012 map — half a zone warmer now. 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 Mc Laughlin, 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 Mc Laughlin, SD

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 12median — 50% chance of a later frost
Safe for tender plantsMay 25only 10% chance of frost after
First fall frostSeptember 28median — 10% chance by Sep 16
Growing season137 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 3 and returns around October 5.

From the NOAA station Mc Laughlin, SD — 5 miles away, elevation 2,001 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 57642

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 31 – Apr 14
SpinachSow outdoors · Mar 31 – Apr 21
Broccoli, cabbageStart indoors · Mar 3 – Mar 17
Broccoli, cabbageTransplant · Apr 21 – May 5
Onion setsPlant outdoors · Apr 14 – Apr 28
PotatoesPlant outdoors · Apr 21 – May 5
LettuceSow outdoors · Apr 14 – Apr 28
Carrots, beetsSow outdoors · Apr 21 – May 5
TomatoesStart indoors · Mar 17 – Mar 31
TomatoesTransplant · May 19 – Jun 2
Peppers, eggplantStart indoors · Mar 3 – Mar 17
Peppers, eggplantTransplant · May 26 – Jun 9
BeansSow outdoors · May 19 – Jun 2
Sweet cornSow outdoors · May 19 – Jun 2
Cucumbers, squashSow outdoors · May 19 – Jun 2
Fall lettuce, spinachSow outdoors · Aug 3 – Aug 17
GarlicPlant cloves · Sep 14 – Oct 19
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 12) and first fall frost (Sep 28) 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 57642 came on Apr 8 — 8 days earlier than the 1991–2020 average (Apr 16).

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 Mc Laughlin, SD.

Soil in Mc Laughlin, SD

The soil mapped at the center of ZIP 57642 is Shambo — loam, well drained.

TextureLoama good balance for most vegetables
pH7.0neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter4%moderate
Hydrologic groupBwater soaks in moderately
Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Shambo loam, 2 to 6 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 57642; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Mc Laughlin, SD

Summer high85 °Faverage high, July
Winter low4 °Faverage low, January
Hot days24days a year at 90 °F or more
Freezing nights186nights a year at 32 °F or less
Growing degree days2,370base 50 °F — the season’s usable heat
Longest day15 h 43 mindaylight on June 21
Shortest day8 h 40 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation20.1 inper year, rain and melted snow
Snowfall35 inper year

Average high and low, by month

−10°0°10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 24 °F, low 4 °F 24°4° JanFebruary: average high 28 °F, low 7 °F 28°7° FebMarch: average high 42 °F, low 19 °F 42°19° MarApril: average high 56 °F, low 30 °F 56°30° AprMay: average high 68 °F, low 42 °F 68°42° MayJune: average high 78 °F, low 53 °F 78°53° JunJuly: average high 85 °F, low 58 °F 85°58° JulAugust: average high 84 °F, low 55 °F 84°55° AugSeptember: average high 74 °F, low 45 °F 74°45° SepOctober: average high 57 °F, low 32 °F 57°32° OctNovember: average high 41 °F, low 19 °F 41°19° NovDecember: average high 29 °F, low 9 °F 29°9° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″January: 0.50 in precipitation, 7.5 in snowfall 0.5❄8 JanFebruary: 0.49 in precipitation, 6.5 in snowfall 0.5❄7 FebMarch: 0.94 in precipitation, 3.7 in snowfall 0.9❄4 MarApril: 1.69 in precipitation, 2.1 in snowfall 1.7❄2 AprMay: 3.17 in precipitation, 0.2 in snowfall 3.2 MayJune: 3.34 in precipitation 3.3 JunJuly: 3.03 in precipitation 3.0 JulAugust: 2.47 in precipitation 2.5 AugSeptember: 1.45 in precipitation 1.4 SepOctober: 1.77 in precipitation, 0.7 in snowfall 1.8❄1 OctNovember: 0.65 in precipitation, 4 in snowfall 0.7❄4 NovDecember: 0.58 in precipitation, 10.2 in snowfall 0.6❄10 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Mc Laughlin, SD (5 mi away); precipitation: Mc Laughlin, SD (5 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

3 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

576394a
Little Eagle, SD · 9 mi
576584b
Wakpala, SD · 11 mi
576214b
Bullhead, SD · 18 mi
576574b
Trail City, SD · 19 mi
576594b
Walker, SD · 20 mi
585384a
Fort Yates, ND · 20 mi
576484a
Pollock, SD · 21 mi
576314b
Glenham, SD · 25 mi

South Dakota planting zones →

Questions about 57642

What planting zone is ZIP code 57642?

ZIP code 57642 (Mc Laughlin, 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 Mc Laughlin, SD?

The median last spring frost (32 °F) near 57642 is May 12; after May 25 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Mc Laughlin station.

When is the first frost in Mc Laughlin, SD?

The median first fall frost near 57642 is September 28, giving a median frost-free growing season of 137 days.

When should I plant tomatoes in 57642?

Start tomato seeds indoors around Mar 17 – Mar 31 and set transplants outside around May 19 – Jun 2, one to three weeks after the median last frost.

How much rain and snow does 57642 get?

About 20.1 inches of precipitation a year and 35 inches of snowfall (NOAA 1991–2020 normals, Mc Laughlin station).

How hot do summers get in Mc Laughlin, SD?

The average high peaks at 85 °F in July, with about 24 days a year at 90 °F or more.

What kind of soil does 57642 have?

The USDA soil survey maps Shambo at the center of ZIP 57642: loam, well drained, pH about 7.0 (neutral).

Did spring come early in Mc Laughlin, SD in 2026?

Spring leaf-out near 57642 came on Apr 8 in 2026, 8 days earlier than the 1991–2020 average (Apr 16), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Mc Laughlin, SD?

Long-day onions: the longest day near 57642 is 15 h 43 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 57642 change?

Yes. The 2012 USDA map put 57642 in zone 4a; the 2023 map puts it in zone 4b. The newer map uses 1991–2020 data and more weather stations.