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

Planting zone for 58531 — Coleharbor, ND

ZIP code 58531 (Coleharbor, McLean County) is in USDA zone 4a: the coldest winter night averages −30 to −25 °F. The median last spring frost is May 12 and the first fall frost October 3.

Where ZIP 58531 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 12
First frostOct 3
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 Coleharbor, 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 Coleharbor, ND

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 27only 10% chance of frost after
First fall frostOctober 3median — 10% chance by Sep 20
Growing season143 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 1 and returns around October 12.

From the NOAA station Riverdale, ND — 9 miles away, elevation 1,962 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 58531

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 8 – Aug 22
GarlicPlant cloves · Sep 19 – Oct 24
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 12) and first fall frost (Oct 3) 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 58531 came on Apr 21 — about the same time as the 1991–2020 average (Apr 22).

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 Coleharbor, ND.

Soil in Coleharbor, ND

The soil mapped at the center of ZIP 58531 is Makoti — silty clay loam, moderately well drained.

TextureSilty clay loamholds water and nutrients; slow to drain and warm up
pH7.0neutral; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter5%high
Hydrologic groupBwater soaks in moderately
Farmland classprime farmlandUSDA classification

Map unit: Makoti silty clay loam, 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 58531; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Coleharbor, ND

Summer high81 °Faverage high, July
Winter low3 °Faverage low, January
Hot days13days a year at 90 °F or more
Freezing nights178nights a year at 32 °F or less
Growing degree days2,146base 50 °F — the season’s usable heat
Longest day15 h 59 mindaylight on June 21
Shortest day8 h 26 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation18 inper year, rain and melted snow
Snowfall39 inper year; 87 days with snow on the ground

Average high and low, by month

−10°0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 20 °F, low 3 °F 20°3° JanFebruary: average high 24 °F, low 7 °F 24°7° FebMarch: average high 37 °F, low 18 °F 37°18° MarApril: average high 52 °F, low 31 °F 52°31° AprMay: average high 65 °F, low 42 °F 65°42° MayJune: average high 74 °F, low 53 °F 74°53° JunJuly: average high 81 °F, low 59 °F 81°59° JulAugust: average high 80 °F, low 57 °F 80°57° AugSeptember: average high 71 °F, low 48 °F 71°48° SepOctober: average high 54 °F, low 36 °F 54°36° OctNovember: average high 37 °F, low 21 °F 37°21° NovDecember: average high 25 °F, low 11 °F 25°11° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″January: 0.54 in precipitation, 6.7 in snowfall 0.5❄7 JanFebruary: 0.50 in precipitation, 5 in snowfall 0.5❄5 FebMarch: 0.78 in precipitation, 6.8 in snowfall 0.8❄7 MarApril: 1.39 in precipitation, 2.7 in snowfall 1.4❄3 AprMay: 2.59 in precipitation, 0.7 in snowfall 2.6❄1 MayJune: 3.78 in precipitation 3.8 JunJuly: 2.44 in precipitation 2.4 JulAugust: 1.68 in precipitation 1.7 AugSeptember: 1.56 in precipitation 1.6 SepOctober: 1.41 in precipitation, 1.6 in snowfall 1.4❄2 OctNovember: 0.73 in precipitation, 4.2 in snowfall 0.7❄4 NovDecember: 0.63 in precipitation, 10.9 in snowfall 0.6❄11 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Riverdale, ND (9 mi away); precipitation: Underwood, ND (9 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 4a.

585654a
Riverdale, ND · 9 mi
585764a
Underwood, ND · 10 mi
585754a
Turtle Lake, ND · 16 mi
587164a
Benedict, ND · 17 mi
587594a
Max, ND · 18 mi
585774a
Washburn, ND · 20 mi
587784a
Ruso, ND · 21 mi
585714a
Stanton, ND · 21 mi

North Dakota planting zones →

Questions about 58531

What planting zone is ZIP code 58531?

ZIP code 58531 (Coleharbor, 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 Coleharbor, ND?

The median last spring frost (32 °F) near 58531 is May 12; after May 27 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Riverdale station.

When is the first frost in Coleharbor, ND?

The median first fall frost near 58531 is October 3, giving a median frost-free growing season of 143 days.

When should I plant tomatoes in 58531?

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 58531 get?

About 18 inches of precipitation a year and 39 inches of snowfall (NOAA 1991–2020 normals, Underwood station).

How hot do summers get in Coleharbor, ND?

The average high peaks at 81 °F in July, with about 13 days a year at 90 °F or more.

What kind of soil does 58531 have?

The USDA soil survey maps Makoti at the center of ZIP 58531: silty clay loam, moderately well drained, pH about 7.0 (neutral).

Did spring come early in Coleharbor, ND in 2026?

Spring leaf-out near 58531 came on Apr 21 in 2026, about the same as the 1991–2020 average (Apr 22), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Coleharbor, ND?

Long-day onions: the longest day near 58531 is 15 h 59 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).