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

Planting zone for 57359 — Letcher, SD

ZIP code 57359 (Letcher, Sanborn County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is April 27 and the first fall frost October 11.

Where ZIP 57359 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.

Zone5a−20 to −15 °F
Coldest night−28.9 to −26.1 °C
Last frostApr 27
First frostOct 11
2012 zone4b

Was 4b 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 5a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Letcher, 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 Letcher, SD

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 27median — 50% chance of a later frost
Safe for tender plantsMay 10only 10% chance of frost after
First fall frostOctober 11median — 10% chance by Sep 30
Growing season167 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 17 and returns around October 21.

From the NOAA station Mitchell, SD — 11 miles away, elevation 1,286 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 57359

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 16 – Mar 30
SpinachSow outdoors · Mar 16 – Apr 6
Broccoli, cabbageStart indoors · Feb 16 – Mar 2
Broccoli, cabbageTransplant · Apr 6 – Apr 20
Onion setsPlant outdoors · Mar 30 – Apr 13
PotatoesPlant outdoors · Apr 6 – Apr 20
LettuceSow outdoors · Mar 30 – Apr 13
Carrots, beetsSow outdoors · Apr 6 – Apr 20
TomatoesStart indoors · Mar 2 – Mar 16
TomatoesTransplant · May 4 – May 18
Peppers, eggplantStart indoors · Feb 16 – Mar 2
Peppers, eggplantTransplant · May 11 – May 25
BeansSow outdoors · May 4 – May 18
Sweet cornSow outdoors · May 4 – May 18
Cucumbers, squashSow outdoors · May 4 – May 18
Fall lettuce, spinachSow outdoors · Aug 16 – Aug 30
GarlicPlant cloves · Sep 27 – Nov 1
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 27) and first fall frost (Oct 11) 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 57359 came on Mar 24 — 18 days earlier than the 1991–2020 average (Apr 11).

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 5a in South Dakota

452 plants native to the lower 48 states, recorded in South Dakota, and rated by the USDA to survive −20 °F or colder — the bottom of zone 5a. 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 70

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 202

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 144

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 Letcher, SD.

Soil in Letcher, SD

The soil mapped at the center of ZIP 57359 is Carthage — fine sandy loam, moderately well drained.

TextureFine sandy loamdrains and warms fast; dries out and needs more feeding
pH6.7neutral; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter3%moderate
Hydrologic groupCwater soaks in slowly
Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Carthage-Hand fine sandy loams, 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 57359; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Letcher, SD

Summer high87 °Faverage high, July
Winter low9 °Faverage low, January
Hot days30days a year at 90 °F or more
Freezing nights152nights a year at 32 °F or less
Growing degree days3,132base 50 °F — the season’s usable heat
Longest day15 h 28 mindaylight on June 21
Shortest day8 h 54 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation25.8 inper year, rain and melted snow
Snowfall41 inper year; 78 days with snow on the ground

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 27 °F, low 9 °F 27°9° JanFebruary: average high 32 °F, low 13 °F 32°13° FebMarch: average high 45 °F, low 25 °F 45°25° MarApril: average high 59 °F, low 37 °F 59°37° AprMay: average high 70 °F, low 49 °F 70°49° MayJune: average high 81 °F, low 60 °F 81°60° JunJuly: average high 87 °F, low 65 °F 87°65° JulAugust: average high 84 °F, low 62 °F 84°62° AugSeptember: average high 76 °F, low 53 °F 76°53° SepOctober: average high 61 °F, low 39 °F 61°39° OctNovember: average high 45 °F, low 26 °F 45°26° NovDecember: average high 31 °F, low 15 °F 31°15° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″January: 0.61 in precipitation, 5.6 in snowfall 0.6❄6 JanFebruary: 0.76 in precipitation, 8.3 in snowfall 0.8❄8 FebMarch: 1.26 in precipitation, 5.8 in snowfall 1.3❄6 MarApril: 2.76 in precipitation, 6 in snowfall 2.8❄6 AprMay: 3.69 in precipitation 3.7 MayJune: 3.95 in precipitation 4.0 JunJuly: 3.02 in precipitation 3.0 JulAugust: 3.09 in precipitation 3.1 AugSeptember: 2.64 in precipitation 2.6 SepOctober: 2.11 in precipitation, 0.6 in snowfall 2.1❄1 OctNovember: 1.12 in precipitation, 4.1 in snowfall 1.1❄4 NovDecember: 0.77 in precipitation, 10.2 in snowfall 0.8❄10 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Mitchell, SD (11 mi away); precipitation: Mitchell, SD (11 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

573855a
Woonsocket, SD · 12 mi
573144b
Artesian, SD · 13 mi
573015a
Mitchell, SD · 14 mi
573635a
Mount Vernon, SD · 16 mi
573405a
Fulton, SD · 17 mi
573585a
Lane, SD · 18 mi
573685a
Plankinton, SD · 19 mi
573375a
Fedora, SD · 20 mi

South Dakota planting zones →

Questions about 57359

What planting zone is ZIP code 57359?

ZIP code 57359 (Letcher, SD) is in USDA hardiness zone 5a on the 2023 map: the coldest night of an average winter reaches −20 to −15 °F (−28.9 to −26.1 °C).

When is the last frost in Letcher, SD?

The median last spring frost (32 °F) near 57359 is April 27; after May 10 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Mitchell station.

When is the first frost in Letcher, SD?

The median first fall frost near 57359 is October 11, giving a median frost-free growing season of 167 days.

When should I plant tomatoes in 57359?

Start tomato seeds indoors around Mar 2 – Mar 16 and set transplants outside around May 4 – May 18, one to three weeks after the median last frost.

How much rain and snow does 57359 get?

About 25.8 inches of precipitation a year and 41 inches of snowfall (NOAA 1991–2020 normals, Mitchell station).

How hot do summers get in Letcher, SD?

The average high peaks at 87 °F in July, with about 30 days a year at 90 °F or more.

What kind of soil does 57359 have?

The USDA soil survey maps Carthage at the center of ZIP 57359: fine sandy loam, moderately well drained, pH about 6.7 (neutral).

Did spring come early in Letcher, SD in 2026?

Spring leaf-out near 57359 came on Mar 24 in 2026, 18 days earlier than the 1991–2020 average (Apr 11), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Letcher, SD?

Long-day onions: the longest day near 57359 is 15 h 28 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 57359 change?

Yes. The 2012 USDA map put 57359 in zone 4b; the 2023 map puts it in zone 5a. The newer map uses 1991–2020 data and more weather stations.