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

Planting zone for 58559 — Mercer, ND

ZIP code 58559 (Mercer, McLean County) is in USDA zone 4a: the coldest winter night averages −30 to −25 °F. The median last spring frost is May 14 and the first fall frost September 26.

Where ZIP 58559 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 14
First frostSep 26
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 Mercer, 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 Mercer, ND

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 14median — 50% chance of a later frost
Safe for tender plantsMay 26only 10% chance of frost after
First fall frostSeptember 26median — 10% chance by Sep 15
Growing season136 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 5 and returns around October 5.

From the NOAA station Turtle Lake, ND — 10 miles away, elevation 1,893 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 58559

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 2 – Apr 16
SpinachSow outdoors · Apr 2 – Apr 23
Broccoli, cabbageStart indoors · Mar 5 – Mar 19
Broccoli, cabbageTransplant · Apr 23 – May 7
Onion setsPlant outdoors · Apr 16 – Apr 30
PotatoesPlant outdoors · Apr 23 – May 7
LettuceSow outdoors · Apr 16 – Apr 30
Carrots, beetsSow outdoors · Apr 23 – May 7
TomatoesStart indoors · Mar 19 – Apr 2
TomatoesTransplant · May 21 – Jun 4
Peppers, eggplantStart indoors · Mar 5 – Mar 19
Peppers, eggplantTransplant · May 28 – Jun 11
BeansSow outdoors · May 21 – Jun 4
Sweet cornSow outdoors · May 21 – Jun 4
Cucumbers, squashSow outdoors · May 21 – Jun 4
Fall lettuce, spinachSow outdoors · Aug 1 – Aug 15
GarlicPlant cloves · Sep 12 – Oct 17
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 14) and first fall frost (Sep 26) 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 58559 came on Apr 21 — about the same time as the 1991–2020 average (Apr 23).

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 Mercer, ND.

Soil in Mercer, ND

The soil mapped at the center of ZIP 58559 is Wabek — loam, excessively drained.

TextureLoama good balance for most vegetables
pH7.0neutral; most vegetables like 6.0–7.0
DrainageExcessively drainednatural drainage class
Organic matter2%moderate
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Wabek-Lehr-Appam complex, 9 to 25 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 58559; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Mercer, ND

Summer high83 °Faverage high, July
Winter low1 °Faverage low, January
Hot days15days a year at 90 °F or more
Freezing nights195nights a year at 32 °F or less
Growing degree days2,112base 50 °F — the season’s usable heat
Longest day15 h 58 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)
Precipitation18.2 inper year, rain and melted snow
Snowfall44 inper year

Average high and low, by month

−10°0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 20 °F, low 1 °F 20°1° JanFebruary: average high 25 °F, low 4 °F 25°4° FebMarch: average high 37 °F, low 16 °F 37°16° MarApril: average high 54 °F, low 28 °F 54°28° AprMay: average high 67 °F, low 40 °F 67°40° MayJune: average high 76 °F, low 51 °F 76°51° JunJuly: average high 83 °F, low 56 °F 83°56° JulAugust: average high 82 °F, low 54 °F 82°54° AugSeptember: average high 72 °F, low 44 °F 72°44° SepOctober: average high 55 °F, low 32 °F 55°32° OctNovember: average high 38 °F, low 19 °F 38°19° NovDecember: average high 25 °F, low 7 °F 25°7° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″January: 0.55 in precipitation, 10.5 in snowfall 0.6❄11 JanFebruary: 0.42 in precipitation, 6.5 in snowfall 0.4❄7 FebMarch: 0.84 in precipitation, 5.7 in snowfall 0.8❄6 MarApril: 1.32 in precipitation, 2.3 in snowfall 1.3❄2 AprMay: 2.56 in precipitation, 0.6 in snowfall 2.6❄1 MayJune: 3.47 in precipitation 3.5 JunJuly: 2.58 in precipitation 2.6 JulAugust: 2.19 in precipitation 2.2 AugSeptember: 1.76 in precipitation 1.8 SepOctober: 1.29 in precipitation, 1.7 in snowfall 1.3❄2 OctNovember: 0.61 in precipitation, 8.9 in snowfall 0.6❄9 NovDecember: 0.63 in precipitation, 7.9 in snowfall 0.6❄8 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Turtle Lake, ND (10 mi away); precipitation: Turtle Lake, ND (10 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

584634b
Mcclusky, ND · 10 mi
585754a
Turtle Lake, ND · 11 mi
584774a
Regan, ND · 19 mi
587234a
Butte, ND · 19 mi
585774a
Washburn, ND · 20 mi
585794a
Wilton, ND · 20 mi
584304a
Denhoff, ND · 21 mi
587784a
Ruso, ND · 24 mi

North Dakota planting zones →

Questions about 58559

What planting zone is ZIP code 58559?

ZIP code 58559 (Mercer, 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 Mercer, ND?

The median last spring frost (32 °F) near 58559 is May 14; after May 26 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Turtle Lake station.

When is the first frost in Mercer, ND?

The median first fall frost near 58559 is September 26, giving a median frost-free growing season of 136 days.

When should I plant tomatoes in 58559?

Start tomato seeds indoors around Mar 19 – Apr 2 and set transplants outside around May 21 – Jun 4, one to three weeks after the median last frost.

How much rain and snow does 58559 get?

About 18.2 inches of precipitation a year and 44 inches of snowfall (NOAA 1991–2020 normals, Turtle Lake station).

How hot do summers get in Mercer, ND?

The average high peaks at 83 °F in July, with about 15 days a year at 90 °F or more.

What kind of soil does 58559 have?

The USDA soil survey maps Wabek at the center of ZIP 58559: loam, excessively drained, pH about 7.0 (neutral).

Did spring come early in Mercer, ND in 2026?

Spring leaf-out near 58559 came on Apr 21 in 2026, about the same as the 1991–2020 average (Apr 23), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Mercer, ND?

Long-day onions: the longest day near 58559 is 15 h 58 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).