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

Planting zone for 55738 — Forbes, MN

ZIP code 55738 (Forbes, St. Louis County) is in USDA zone 3b: the coldest winter night averages −35 to −30 °F. The median last spring frost is May 27 and the first fall frost September 20.

Where ZIP 55738 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 27
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 Forbes, MN…

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 Forbes, MN

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 27median — 50% chance of a later frost
Safe for tender plantsJune 11only 10% chance of frost after
First fall frostSeptember 20median — 10% chance by Sep 4
Growing season115 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 14 and returns around October 1.

From the NOAA station Cotton, MN — 11 miles away, elevation 1,322 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 55738

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 15 – Apr 29
SpinachSow outdoors · Apr 15 – May 6
Broccoli, cabbageStart indoors · Mar 18 – Apr 1
Broccoli, cabbageTransplant · May 6 – May 20
Onion setsPlant outdoors · Apr 29 – May 13
PotatoesPlant outdoors · May 6 – May 20
LettuceSow outdoors · Apr 29 – May 13
Carrots, beetsSow outdoors · May 6 – May 20
TomatoesStart indoors · Apr 1 – Apr 15
TomatoesTransplant · Jun 3 – Jun 17
Peppers, eggplantStart indoors · Mar 18 – Apr 1
Peppers, eggplantTransplant · Jun 10 – Jun 24
BeansSow outdoors · Jun 3 – Jun 17
Sweet cornSow outdoors · Jun 3 – Jun 17
Cucumbers, squashSow outdoors · Jun 3 – Jun 17
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 27) 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 55738 came on Apr 24 — 4 days earlier than the 1991–2020 average (Apr 28).

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 Minnesota

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

Trees 33

American basswood100 ft · blooms late spring · low shade tolerance · to −46 °FAmerican beech80 ft · blooms mid spring · low shade tolerance · to −44 °FAmerican elm120 ft · blooms early spring · medium shade tolerance · to −46 °Fbalsam fir60 ft · blooms mid summer · low shade tolerance · to −43 °Fbalsam poplar80 ft · blooms late spring · high shade tolerance · to −79 °Fbigtooth aspen65 ft · blooms mid spring · high shade tolerance · to −43 °F

Shrubs 50

Allegheny serviceberry35 ft · blooms early spring · low shade tolerance · to −38 °Falternateleaf dogwood25 ft · blooms mid spring · low shade tolerance · to −47 °FAmerican black currant3 ft · blooms early spring · to −46 °FAmerican mountain ash40 ft · blooms early summer · medium shade tolerance · to −38 °FAmerican plum24 ft · blooms mid spring · high shade tolerance · to −38 °Fbeaked hazelnut15 ft · blooms early spring · low shade tolerance · to −47 °F

Wildflowers & perennials 102

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine bistort1 ft · blooms mid spring · high shade tolerance · to −38 °FAmerican licorice4 ft · blooms late spring · medium shade tolerance · to −38 °FAmerican lotus3 ft · blooms mid summer · high shade tolerance · to −36 °FAmerican speedwell0.8 ft · blooms mid summer · low shade tolerance · to −38 °FAmerican vetch1.3 ft · blooms late spring · high shade tolerance · to −38 °F

Grasses 93

alkali cordgrass3 ft · blooms late summer · high shade tolerance · to −38 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °Fbasin wildrye5 ft · blooms early spring · high shade tolerance · to −43 °Fbeaked sedge4 ft · blooms late spring · low shade tolerance · to −38 °FBebb's sedge3 ft · blooms late spring · low shade tolerance · to −38 °FBicknell's sedge3 ft · blooms late spring · low shade tolerance · to −38 °F

Vines 2

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °Fdevil's darning needles15 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 Forbes, MN.

Soil in Forbes, MN

The soil mapped at the center of ZIP 55738 is Majestic — sandy loam, moderately well drained.

TextureSandy loamdrains and warms fast; dries out and needs more feeding
pH5.2strongly acidic; 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: Majestic-Hibbing complex, 2 to 8 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 55738; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Forbes, MN

Summer high78 °Faverage high, July
Winter low−5 °Faverage low, January
Hot days3days a year at 90 °F or more
Freezing nights207nights a year at 32 °F or less
Growing degree days1,559base 50 °F — the season’s usable heat
Longest day15 h 56 mindaylight on June 21
Shortest day8 h 28 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation29.2 inper year, rain and melted snow

Average high and low, by month

−20°−10°0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 18 °F, low -5 °F 18°−5° JanFebruary: average high 25 °F, low -4 °F 25°−4° FebMarch: average high 37 °F, low 12 °F 37°12° MarApril: average high 50 °F, low 25 °F 50°25° AprMay: average high 64 °F, low 38 °F 64°38° MayJune: average high 73 °F, low 48 °F 73°48° JunJuly: average high 78 °F, low 52 °F 78°52° JulAugust: average high 76 °F, low 50 °F 76°50° AugSeptember: average high 67 °F, low 43 °F 67°43° SepOctober: average high 52 °F, low 32 °F 52°32° OctNovember: average high 37 °F, low 18 °F 37°18° NovDecember: average high 24 °F, low 3 °F 24°3° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 0.73 in precipitation 0.7 JanFebruary: 0.85 in precipitation 0.8 FebMarch: 1.13 in precipitation 1.1 MarApril: 2.30 in precipitation 2.3 AprMay: 3.21 in precipitation 3.2 MayJune: 4.48 in precipitation 4.5 JunJuly: 4.19 in precipitation 4.2 JulAugust: 3.61 in precipitation 3.6 AugSeptember: 3.38 in precipitation 3.4 SepOctober: 2.71 in precipitation 2.7 OctNovember: 1.50 in precipitation 1.5 NovDecember: 1.09 in precipitation 1.1 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Cotton, MN (11 mi away); precipitation: Cotton, MN (11 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 3b.

557513b
Iron, MN · 9 mi
557343b
Eveleth, MN · 12 mi
557663b
Melrude, MN · 12 mi
557653b
Meadowlands, MN · 12 mi
557463b
Hibbing, MN · 15 mi
557243b
Cotton, MN · 15 mi
557133b
Buhl, MN · 16 mi
557583b
Kinney, MN · 17 mi

Minnesota planting zones →

Questions about 55738

What planting zone is ZIP code 55738?

ZIP code 55738 (Forbes, MN) 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 Forbes, MN?

The median last spring frost (32 °F) near 55738 is May 27; after June 11 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Cotton station.

When is the first frost in Forbes, MN?

The median first fall frost near 55738 is September 20, giving a median frost-free growing season of 115 days.

When should I plant tomatoes in 55738?

Start tomato seeds indoors around Apr 1 – Apr 15 and set transplants outside around Jun 3 – Jun 17, one to three weeks after the median last frost.

How much rain and snow does 55738 get?

About 29.2 inches of precipitation a year (NOAA 1991–2020 normals, Cotton station).

How hot do summers get in Forbes, MN?

The average high peaks at 78 °F in July, with about 3 days a year at 90 °F or more.

What kind of soil does 55738 have?

The USDA soil survey maps Majestic at the center of ZIP 55738: sandy loam, moderately well drained, pH about 5.2 (strongly acidic).

Did spring come early in Forbes, MN in 2026?

Spring leaf-out near 55738 came on Apr 24 in 2026, 4 days earlier than the 1991–2020 average (Apr 28), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Forbes, MN?

Long-day onions: the longest day near 55738 is 15 h 56 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).