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

Planting zone for 57429 — Brentford, SD

ZIP code 57429 (Brentford, Spink County) is in USDA zone 4a: the coldest winter night averages −30 to −25 °F. The median last spring frost is May 6 and the first fall frost September 29.

Where ZIP 57429 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.

Zone4a−30 to −25 °F
Coldest night−34.4 to −31.7 °C
Last frostMay 6
First frostSep 29
2012 zone4a

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 4a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Brentford, 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 Brentford, SD

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 6median — 50% chance of a later frost
Safe for tender plantsMay 20only 10% chance of frost after
First fall frostSeptember 29median — 10% chance by Sep 16
Growing season144 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 29 and returns around October 7.

From the NOAA station Conde, SD — 10 miles away, elevation 1,329 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 57429

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 25 – Apr 8
SpinachSow outdoors · Mar 25 – Apr 15
Broccoli, cabbageStart indoors · Feb 25 – Mar 11
Broccoli, cabbageTransplant · Apr 15 – Apr 29
Onion setsPlant outdoors · Apr 8 – Apr 22
PotatoesPlant outdoors · Apr 15 – Apr 29
LettuceSow outdoors · Apr 8 – Apr 22
Carrots, beetsSow outdoors · Apr 15 – Apr 29
TomatoesStart indoors · Mar 11 – Mar 25
TomatoesTransplant · May 13 – May 27
Peppers, eggplantStart indoors · Feb 25 – Mar 11
Peppers, eggplantTransplant · May 20 – Jun 3
BeansSow outdoors · May 13 – May 27
Sweet cornSow outdoors · May 13 – May 27
Cucumbers, squashSow outdoors · May 13 – May 27
Fall lettuce, spinachSow outdoors · Aug 4 – Aug 18
GarlicPlant cloves · Sep 15 – Oct 20
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 6) and first fall frost (Sep 29) 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 57429 came on Apr 8 — 9 days earlier than the 1991–2020 average (Apr 17).

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 4a in South Dakota

384 plants native to the lower 48 states, recorded in South Dakota, and rated by the USDA to survive −30 °F or colder — the bottom of zone 4a. Each links to its USDA PLANTS profile.

Trees 21

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 °Fboxelder60 ft · blooms early spring · low shade tolerance · to −46 °F

Shrubs 62

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 165

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 126

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 4

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 °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 Brentford, SD.

Soil in Brentford, SD

The soil mapped at the center of ZIP 57429 is Harmony — silty clay loam, moderately well drained.

TextureSilty clay loamholds water and nutrients; slow to drain and warm up
pH6.7neutral; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter6%high
Hydrologic groupCwater soaks in slowly
Farmland classFarmland of statewide importanceUSDA classification

Map unit: Harmony-Aberdeen silty clay loams, 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 57429; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Brentford, SD

Summer high84 °Faverage high, July
Winter low2 °Faverage low, January
Hot days16days a year at 90 °F or more
Freezing nights182nights a year at 32 °F or less
Growing degree days2,516base 50 °F — the season’s usable heat
Longest day15 h 38 mindaylight on June 21
Shortest day8 h 45 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation22.4 inper year, rain and melted snow
Snowfall34 inper year

Average high and low, by month

−10°0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 23 °F, low 2 °F 23°2° JanFebruary: average high 28 °F, low 6 °F 28°6° FebMarch: average high 40 °F, low 19 °F 40°19° MarApril: average high 56 °F, low 31 °F 56°31° AprMay: average high 68 °F, low 44 °F 68°44° MayJune: average high 78 °F, low 55 °F 78°55° JunJuly: average high 84 °F, low 60 °F 84°60° JulAugust: average high 82 °F, low 57 °F 82°57° AugSeptember: average high 74 °F, low 48 °F 74°48° SepOctober: average high 60 °F, low 34 °F 60°34° OctNovember: average high 42 °F, low 20 °F 42°20° NovDecember: average high 29 °F, low 8 °F 29°8° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″January: 0.38 in precipitation, 5.2 in snowfall 0.4❄5 JanFebruary: 0.50 in precipitation, 7.5 in snowfall 0.5❄8 FebMarch: 0.89 in precipitation, 5.5 in snowfall 0.9❄6 MarApril: 2.09 in precipitation, 1.2 in snowfall 2.1❄1 AprMay: 3.47 in precipitation 3.5 MayJune: 3.63 in precipitation 3.6 JunJuly: 3.55 in precipitation 3.5 JulAugust: 2.12 in precipitation 2.1 AugSeptember: 2.14 in precipitation 2.1 SepOctober: 2.33 in precipitation, 0.8 in snowfall 2.3❄1 OctNovember: 0.83 in precipitation, 3.2 in snowfall 0.8❄3 NovDecember: 0.51 in precipitation, 10.7 in snowfall 0.5❄11 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Conde, SD (10 mi away); precipitation: Stratford 7sw, SD (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

574614a
Mellette, SD · 7 mi
574744a
Stratford, SD · 9 mi
574344a
Conde, SD · 11 mi
574774b
Turton, SD · 12 mi
574794a
Warner, SD · 12 mi
574244b
Ashton, SD · 15 mi
574394a
Ferney, SD · 15 mi
574654a
Northville, SD · 18 mi

South Dakota planting zones →

Questions about 57429

What planting zone is ZIP code 57429?

ZIP code 57429 (Brentford, SD) is in USDA hardiness zone 4a on the 2023 map: the coldest night of an average winter reaches −30 to −25 °F (−34.4 to −31.7 °C).

When is the last frost in Brentford, SD?

The median last spring frost (32 °F) near 57429 is May 6; after May 20 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Conde station.

When is the first frost in Brentford, SD?

The median first fall frost near 57429 is September 29, giving a median frost-free growing season of 144 days.

When should I plant tomatoes in 57429?

Start tomato seeds indoors around Mar 11 – Mar 25 and set transplants outside around May 13 – May 27, one to three weeks after the median last frost.

How much rain and snow does 57429 get?

About 22.4 inches of precipitation a year and 34 inches of snowfall (NOAA 1991–2020 normals, Stratford 7sw station).

How hot do summers get in Brentford, 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 57429 have?

The USDA soil survey maps Harmony at the center of ZIP 57429: silty clay loam, moderately well drained, pH about 6.7 (neutral).

Did spring come early in Brentford, SD in 2026?

Spring leaf-out near 57429 came on Apr 8 in 2026, 9 days earlier than the 1991–2020 average (Apr 17), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Brentford, SD?

Long-day onions: the longest day near 57429 is 15 h 38 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).