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

Planting zone for 57745 — Hill City, SD

ZIP code 57745 (Hill City, Pennington County) is in USDA zone 4b: the coldest winter night averages −25 to −20 °F. The median last spring frost is June 1 and the first fall frost September 10.

Where ZIP 57745 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 frostJun 1
First frostSep 10
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 Hill City, 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 Hill City, SD

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostJune 1median — 50% chance of a later frost
Safe for tender plantsJune 19only 10% chance of frost after
First fall frostSeptember 10median — 10% chance by Aug 29
Growing season102 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 18 and returns around September 21.

From the NOAA station Hill City, SD — 12 miles away, elevation 4,948 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 57745

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 20 – May 4
SpinachSow outdoors · Apr 20 – May 11
Broccoli, cabbageStart indoors · Mar 23 – Apr 6
Broccoli, cabbageTransplant · May 11 – May 25
Onion setsPlant outdoors · May 4 – May 18
PotatoesPlant outdoors · May 11 – May 25
LettuceSow outdoors · May 4 – May 18
Carrots, beetsSow outdoors · May 11 – May 25
TomatoesStart indoors · Apr 6 – Apr 20
TomatoesTransplant · Jun 8 – Jun 22
Peppers, eggplantStart indoors · Mar 23 – Apr 6
Peppers, eggplantTransplant · Jun 15 – Jun 29
BeansSow outdoors · Jun 8 – Jun 22
Sweet cornSow outdoors · Jun 8 – Jun 22
Cucumbers, squashSow outdoors · Jun 8 – Jun 22
Fall lettuce, spinachSow outdoors · Jul 16 – Jul 30
GarlicPlant cloves · Aug 27 – Oct 1
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 1) and first fall frost (Sep 10) 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 57745 came on Apr 21 — 10 days earlier than the 1991–2020 average (May 1).

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 Hill City, SD.

Soil in Hill City, SD

The soil mapped at the center of ZIP 57745 is Virkula — slightly decomposed plant material, well drained.

TextureSlightly decomposed plant materialtop layer
pH5.4strongly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter63%high
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Virkula-Pactola complex, 2 to 15 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 57745; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Hill City, SD

Summer high80 °Faverage high, July
Winter low3 °Faverage low, January
Hot days5days a year at 90 °F or more
Freezing nights255nights a year at 32 °F or less
Growing degree days1,018base 50 °F — the season’s usable heat
Longest day15 h 29 mindaylight on June 21
Shortest day8 h 53 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation27 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 37 °F, low 3 °F 37°3° JanFebruary: average high 37 °F, low 4 °F 37°4° FebMarch: average high 45 °F, low 12 °F 45°12° MarApril: average high 51 °F, low 21 °F 51°21° AprMay: average high 60 °F, low 31 °F 60°31° MayJune: average high 71 °F, low 39 °F 71°39° JunJuly: average high 80 °F, low 44 °F 80°44° JulAugust: average high 79 °F, low 40 °F 79°40° AugSeptember: average high 71 °F, low 32 °F 71°32° SepOctober: average high 56 °F, low 21 °F 56°21° OctNovember: average high 44 °F, low 12 °F 44°12° NovDecember: average high 37 °F, low 6 °F 37°6° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 1.77 in precipitation 1.8 JanFebruary: 1.73 in precipitation 1.7 FebMarch: 1.79 in precipitation 1.8 MarApril: 2.89 in precipitation 2.9 AprMay: 4.08 in precipitation 4.1 MayJune: 3.10 in precipitation 3.1 JunJuly: 2.57 in precipitation 2.6 JulAugust: 1.72 in precipitation 1.7 AugSeptember: 1.58 in precipitation 1.6 SepOctober: 2.45 in precipitation 2.5 OctNovember: 1.80 in precipitation 1.8 NovDecember: 1.49 in precipitation 1.5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Rochford 2 Wnw, SD (8 mi away); precipitation: Blind Park, SD (12 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

577545a
Lead, SD · 17 mi
577025a
Rapid City, SD · 18 mi
577595a
Nemo, SD · 19 mi
577515a
Keystone, SD · 20 mi
577305a
Custer, SD · 21 mi
577325a
Deadwood, SD · 22 mi
577185a
Black Hawk, SD · 23 mi
577095b
Rapid City, SD · 24 mi

South Dakota planting zones →

Questions about 57745

What planting zone is ZIP code 57745?

ZIP code 57745 (Hill City, 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 Hill City, SD?

The median last spring frost (32 °F) near 57745 is June 1; after June 19 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Hill City station.

When is the first frost in Hill City, SD?

The median first fall frost near 57745 is September 10, giving a median frost-free growing season of 102 days.

When should I plant tomatoes in 57745?

Start tomato seeds indoors around Apr 6 – Apr 20 and set transplants outside around Jun 8 – Jun 22, one to three weeks after the median last frost.

How much rain and snow does 57745 get?

About 27 inches of precipitation a year (NOAA 1991–2020 normals, Blind Park station).

How hot do summers get in Hill City, SD?

The average high peaks at 80 °F in July, with about 5 days a year at 90 °F or more.

What kind of soil does 57745 have?

The USDA soil survey maps Virkula at the center of ZIP 57745: slightly decomposed plant material, well drained, pH about 5.4 (strongly acidic).

Did spring come early in Hill City, SD in 2026?

Spring leaf-out near 57745 came on Apr 21 in 2026, 10 days earlier than the 1991–2020 average (May 1), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Hill City, SD?

Long-day onions: the longest day near 57745 is 15 h 29 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 57745 change?

Yes. The 2012 USDA map put 57745 in zone 4a; the 2023 map puts it in zone 4b. The newer map uses 1991–2020 data and more weather stations.