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

Planting zone for 58640 — Killdeer, ND

ZIP code 58640 (Killdeer, Dunn County) is in USDA zone 4a: the coldest winter night averages −30 to −25 °F. The median last spring frost is May 21 and the first fall frost September 23.

Where ZIP 58640 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 21
First frostSep 23
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 Killdeer, 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 Killdeer, ND

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 21median — 50% chance of a later frost
Safe for tender plantsJune 5only 10% chance of frost after
First fall frostSeptember 23median — 10% chance by Sep 8
Growing season124 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 10 and returns around October 1.

From the NOAA station Killdeer, ND — 9 miles away, elevation 2,310 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 58640

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 9 – Apr 23
SpinachSow outdoors · Apr 9 – Apr 30
Broccoli, cabbageStart indoors · Mar 12 – Mar 26
Broccoli, cabbageTransplant · Apr 30 – May 14
Onion setsPlant outdoors · Apr 23 – May 7
PotatoesPlant outdoors · Apr 30 – May 14
LettuceSow outdoors · Apr 23 – May 7
Carrots, beetsSow outdoors · Apr 30 – May 14
TomatoesStart indoors · Mar 26 – Apr 9
TomatoesTransplant · May 28 – Jun 11
Peppers, eggplantStart indoors · Mar 12 – Mar 26
Peppers, eggplantTransplant · Jun 4 – Jun 18
BeansSow outdoors · May 28 – Jun 11
Sweet cornSow outdoors · May 28 – Jun 11
Cucumbers, squashSow outdoors · May 28 – Jun 11
Fall lettuce, spinachSow outdoors · Jul 29 – Aug 12
GarlicPlant cloves · Sep 9 – Oct 14
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 21) and first fall frost (Sep 23) 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 58640 came on Apr 20 — about the same time as the 1991–2020 average (Apr 20).

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 Killdeer, ND.

Soil in Killdeer, ND

The soil mapped at the center of ZIP 58640 is Lakoa — slightly decomposed plant material, well drained.

TextureSlightly decomposed plant materialtop layer
pH6.2slightly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter95%high
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Lakoa loam, 15 to 45 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 58640; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Killdeer, ND

Summer high84 °Faverage high, August
Winter low4 °Faverage low, January
Hot days21days a year at 90 °F or more
Freezing nights191nights a year at 32 °F or less
Growing degree days2,024base 50 °F — the season’s usable heat
Longest day15 h 58 mindaylight on June 21
Shortest day8 h 27 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation18.1 inper year, rain and melted snow
Snowfall39 inper year; 94 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 27 °F, low 4 °F 27°4° JanFebruary: average high 30 °F, low 7 °F 30°7° FebMarch: average high 42 °F, low 18 °F 42°18° MarApril: average high 56 °F, low 28 °F 56°28° AprMay: average high 67 °F, low 39 °F 67°39° MayJune: average high 76 °F, low 49 °F 76°49° JunJuly: average high 83 °F, low 54 °F 83°54° JulAugust: average high 84 °F, low 52 °F 84°52° AugSeptember: average high 73 °F, low 43 °F 73°43° SepOctober: average high 56 °F, low 31 °F 56°31° OctNovember: average high 41 °F, low 18 °F 41°18° NovDecember: average high 30 °F, low 8 °F 30°8° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″January: 0.50 in precipitation, 6.7 in snowfall 0.5❄7 JanFebruary: 0.36 in precipitation, 5.8 in snowfall 0.4❄6 FebMarch: 0.67 in precipitation, 6.7 in snowfall 0.7❄7 MarApril: 1.29 in precipitation, 4.9 in snowfall 1.3❄5 AprMay: 2.81 in precipitation, 1.3 in snowfall 2.8❄1 MayJune: 3.37 in precipitation 3.4 JunJuly: 2.92 in precipitation 2.9 JulAugust: 1.90 in precipitation 1.9 AugSeptember: 1.88 in precipitation 1.9 SepOctober: 1.29 in precipitation, 1.8 in snowfall 1.3❄2 OctNovember: 0.66 in precipitation, 4.8 in snowfall 0.7❄5 NovDecember: 0.49 in precipitation, 7.2 in snowfall 0.5❄7 Dec

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

Nearby ZIP codes

All 8 nearest ZIP codes share zone 4a.

586264a
Dunn Center, ND · 15 mi
586424a
Manning, ND · 18 mi
586344a
Grassy Butte, ND · 21 mi
587574a
Mandaree, ND · 23 mi
586274a
Fairfield, ND · 23 mi
586364a
Halliday, ND · 26 mi
588544a
Watford City, ND · 28 mi
588474a
Keene, ND · 30 mi

North Dakota planting zones →

Questions about 58640

What planting zone is ZIP code 58640?

ZIP code 58640 (Killdeer, 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 Killdeer, ND?

The median last spring frost (32 °F) near 58640 is May 21; after June 5 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Killdeer station.

When is the first frost in Killdeer, ND?

The median first fall frost near 58640 is September 23, giving a median frost-free growing season of 124 days.

When should I plant tomatoes in 58640?

Start tomato seeds indoors around Mar 26 – Apr 9 and set transplants outside around May 28 – Jun 11, one to three weeks after the median last frost.

How much rain and snow does 58640 get?

About 18.1 inches of precipitation a year and 39 inches of snowfall (NOAA 1991–2020 normals, Killdeer station).

How hot do summers get in Killdeer, ND?

The average high peaks at 84 °F in August, with about 21 days a year at 90 °F or more.

What kind of soil does 58640 have?

The USDA soil survey maps Lakoa at the center of ZIP 58640: slightly decomposed plant material, well drained, pH about 6.2 (slightly acidic).

Did spring come early in Killdeer, ND in 2026?

Spring leaf-out near 58640 came on Apr 20 in 2026, about the same as the 1991–2020 average (Apr 20), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Killdeer, ND?

Long-day onions: the longest day near 58640 is 15 h 58 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).