Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 30, 2026

Planting zone for 58830 — Alamo, ND

ZIP code 58830 (Alamo, Williams County) is in USDA zone 3b: the coldest winter night averages −35 to −30 °F. The median last spring frost is May 18 and the first fall frost September 20.

Where ZIP 58830 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.

Zone3b−35 to −30 °F

Coldest night−37.2 to −34.4 °C

Last frostMay 18

First frostSep 20

2012 zone3b

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 3b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Alamo, 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 Alamo, ND

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostMay 18median — 50% chance of a later frost

Safe for tender plantsMay 30only 10% chance of frost after

First fall frostSeptember 20median — 10% chance by Sep 7

Growing season124 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 9 and returns around September 27.

From the NOAA station Wildrose 3nw, ND — 12 miles away, elevation 2,228 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 58830

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 6 – Apr 20

SpinachSow outdoors · Apr 6 – Apr 27

Broccoli, cabbageStart indoors · Mar 9 – Mar 23

Broccoli, cabbageTransplant · Apr 27 – May 11

Onion setsPlant outdoors · Apr 20 – May 4

PotatoesPlant outdoors · Apr 27 – May 11

LettuceSow outdoors · Apr 20 – May 4

Carrots, beetsSow outdoors · Apr 27 – May 11

TomatoesStart indoors · Mar 23 – Apr 6

TomatoesTransplant · May 25 – Jun 8

Peppers, eggplantStart indoors · Mar 9 – Mar 23

Peppers, eggplantTransplant · Jun 1 – Jun 15

BeansSow outdoors · May 25 – Jun 8

Sweet cornSow outdoors · May 25 – Jun 8

Cucumbers, squashSow outdoors · May 25 – Jun 8

Fall lettuce, spinachSow outdoors · Jul 26 – Aug 9

GarlicPlant cloves · Sep 6 – Oct 11

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 18) and first fall frost (Sep 20) 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 58830 came on Apr 24 — about the same time as the 1991–2020 average (Apr 24).

average
Apr 242026
Apr 24

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 3b in North Dakota

249 plants native to the lower 48 states, recorded in North Dakota, and rated by the USDA to survive −35 °F or colder — the bottom of zone 3b. Each links to its USDA PLANTS profile.

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 Alamo, ND.

Soil in Alamo, ND

The soil mapped at the center of ZIP 58830 is Williams — loam, well drained.

TextureLoama good balance for most vegetables

pH7.2neutral; 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: Williams-Zahl loams, 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 58830; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Alamo, ND

Summer high80 °Faverage high, August

Winter low−2 °Faverage low, January

Hot days10days a year at 90 °F or more

Freezing nights200nights a year at 32 °F or less

Growing degree days1,802base 50 °F — the season’s usable heat

Longest day16 h 08 mindaylight on June 21

Shortest day8 h 17 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation16.6 inper year, rain and melted snow

Snowfall37 inper year; 112 days with snow on the ground

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Wildrose 3nw, ND (12 mi away); precipitation: Wildrose 3nw, ND (12 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

North Dakota planting zones →

Questions about 58830

What planting zone is ZIP code 58830?

ZIP code 58830 (Alamo, ND) is in USDA hardiness zone 3b on the 2023 map: the coldest night of an average winter reaches −35 to −30 °F (−37.2 to −34.4 °C).

When is the last frost in Alamo, ND?

The median last spring frost (32 °F) near 58830 is May 18; after May 30 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Wildrose 3nw station.

When is the first frost in Alamo, ND?

The median first fall frost near 58830 is September 20, giving a median frost-free growing season of 124 days.

When should I plant tomatoes in 58830?

Start tomato seeds indoors around Mar 23 – Apr 6 and set transplants outside around May 25 – Jun 8, one to three weeks after the median last frost.

How much rain and snow does 58830 get?

About 16.6 inches of precipitation a year and 37 inches of snowfall (NOAA 1991–2020 normals, Wildrose 3nw station).

How hot do summers get in Alamo, ND?

The average high peaks at 80 °F in August, with about 10 days a year at 90 °F or more.

What kind of soil does 58830 have?

The USDA soil survey maps Williams at the center of ZIP 58830: loam, well drained, pH about 7.2 (neutral).

Did spring come early in Alamo, ND in 2026?

Spring leaf-out near 58830 came on Apr 24 in 2026, about the same as the 1991–2020 average (Apr 24), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Alamo, ND?

Long-day onions: the longest day near 58830 is 16 h 08 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).