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

Planting zone for 58505 — Bismarck, ND

ZIP code 58505 (Bismarck, Burleigh County) is in USDA zone 4a: the coldest winter night averages −30 to −25 °F. The median last spring frost is May 10 and the first fall frost September 30.

Where ZIP 58505 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 10
First frostSep 30
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 Bismarck, ND…

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 Bismarck, ND

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 10median — 50% chance of a later frost
Safe for tender plantsMay 23only 10% chance of frost after
First fall frostSeptember 30median — 10% chance by Sep 16
Growing season142 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 1 and returns around October 9.

From the NOAA station Bismarck 2.4 Nnw, ND — within 1 mile, elevation 1,831 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 58505

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 29 – Apr 12
SpinachSow outdoors · Mar 29 – Apr 19
Broccoli, cabbageStart indoors · Mar 1 – Mar 15
Broccoli, cabbageTransplant · Apr 19 – May 3
Onion setsPlant outdoors · Apr 12 – Apr 26
PotatoesPlant outdoors · Apr 19 – May 3
LettuceSow outdoors · Apr 12 – Apr 26
Carrots, beetsSow outdoors · Apr 19 – May 3
TomatoesStart indoors · Mar 15 – Mar 29
TomatoesTransplant · May 17 – May 31
Peppers, eggplantStart indoors · Mar 1 – Mar 15
Peppers, eggplantTransplant · May 24 – Jun 7
BeansSow outdoors · May 17 – May 31
Sweet cornSow outdoors · May 17 – May 31
Cucumbers, squashSow outdoors · May 17 – May 31
Fall lettuce, spinachSow outdoors · Aug 5 – Aug 19
GarlicPlant cloves · Sep 16 – Oct 21
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 10) and first fall frost (Sep 30) 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 58505 came on Apr 21 — about the same time as 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 4a in North Dakota

342 plants native to the lower 48 states, recorded in North 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 °Fbigtooth aspen65 ft · blooms mid spring · high shade tolerance · to −43 °Fblack ash65 ft · blooms early spring · high shade tolerance · to −47 °Fblack locust60 ft · blooms spring · high shade tolerance · to −37 °F

Shrubs 56

alderleaf buckthorn3 ft · blooms late spring · low shade tolerance · to −33 °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 °Fbig sagebrush4 ft · blooms mid summer · high shade tolerance · to −43 °F

Wildflowers & perennials 146

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine sweetvetch2 ft · blooms early summer · high shade tolerance · to −62 °FAmerican bur-reed3 ft · blooms indeterminate · medium shade tolerance · to −33 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °FAmerican licorice4 ft · blooms late spring · medium shade tolerance · to −38 °FAmerican speedwell0.8 ft · blooms mid summer · low shade tolerance · to −38 °F

Grasses 110

alkali cordgrass3 ft · blooms late summer · high shade tolerance · to −38 °Falkali sacaton3 ft · blooms mid summer · high shade tolerance · to −38 °Fanalogue sedge1.5 ft · blooms late spring · medium shade tolerance · to −38 °Farctic brome3 ft · blooms early summer · low shade tolerance · to −33 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °FBebb's sedge3 ft · blooms late 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 Bismarck, ND.

Soil in Bismarck, ND

The soil mapped at the center of ZIP 58505 is Temvik — silt loam, well drained.

TextureSilt loama 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 classFarmland of statewide importanceUSDA classification

Map unit: Temvik silt loam, 3 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 58505; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Bismarck, ND

Summer high82 °Faverage high, July
Winter low4 °Faverage low, January
Hot days9days a year at 90 °F or more
Freezing nights181nights a year at 32 °F or less
Growing degree days2,158base 50 °F — the season’s usable heat
Longest day15 h 52 mindaylight on June 21
Shortest day8 h 32 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation20 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 4 °F 22°4° JanFebruary: average high 27 °F, low 7 °F 27°7° FebMarch: average high 40 °F, low 18 °F 40°18° MarApril: average high 54 °F, low 29 °F 54°29° AprMay: average high 66 °F, low 43 °F 66°43° MayJune: average high 76 °F, low 53 °F 76°53° JunJuly: average high 82 °F, low 58 °F 82°58° JulAugust: average high 80 °F, low 56 °F 80°56° AugSeptember: average high 71 °F, low 46 °F 71°46° SepOctober: average high 56 °F, low 34 °F 56°34° OctNovember: average high 40 °F, low 20 °F 40°20° NovDecember: average high 27 °F, low 10 °F 27°10° Dec

Precipitation by month inches

0″1″2″3″4″January: 0.55 in precipitation 0.6 JanFebruary: 0.56 in precipitation 0.6 FebMarch: 0.89 in precipitation 0.9 MarApril: 1.44 in precipitation 1.4 AprMay: 2.66 in precipitation 2.7 MayJune: 3.47 in precipitation 3.5 JunJuly: 3.16 in precipitation 3.2 JulAugust: 2.46 in precipitation 2.5 AugSeptember: 1.79 in precipitation 1.8 SepOctober: 1.62 in precipitation 1.6 OctNovember: 0.75 in precipitation 0.8 NovDecember: 0.68 in precipitation 0.7 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Bismarck 2.4 Nnw, ND (within 1 mile); precipitation: Bismarck 1.3 Wnw, ND (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 4a.

585064a
Bismarck, ND · <1 mi
585074a
Bismarck, ND · <1 mi
585014a
Bismarck, ND · 4 mi
585034a
Bismarck, ND · 6 mi
585024a
Bismarck, ND · 7 mi
585044a
Bismarck, ND · 7 mi
585544a
Mandan, ND · 9 mi
585584a
Menoken, ND · 12 mi

All 7 ZIP codes in Bismarck → · North Dakota planting zones →

Questions about 58505

What planting zone is ZIP code 58505?

ZIP code 58505 (Bismarck, ND) 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 Bismarck, ND?

The median last spring frost (32 °F) near 58505 is May 10; after May 23 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Bismarck 2.4 Nnw station.

When is the first frost in Bismarck, ND?

The median first fall frost near 58505 is September 30, giving a median frost-free growing season of 142 days.

When should I plant tomatoes in 58505?

Start tomato seeds indoors around Mar 15 – Mar 29 and set transplants outside around May 17 – May 31, one to three weeks after the median last frost.

How much rain and snow does 58505 get?

About 20 inches of precipitation a year (NOAA 1991–2020 normals, Bismarck 1.3 Wnw station).

How hot do summers get in Bismarck, ND?

The average high peaks at 82 °F in July, with about 9 days a year at 90 °F or more.

What kind of soil does 58505 have?

The USDA soil survey maps Temvik at the center of ZIP 58505: silt loam, well drained, pH about 7.0 (neutral).

Did spring come early in Bismarck, ND in 2026?

Spring leaf-out near 58505 came on Apr 21 in 2026, about the same as the 1991–2020 average (Apr 19), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Bismarck, ND?

Long-day onions: the longest day near 58505 is 15 h 52 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).