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

Planting zone for 54847 — Iron River, WI

ZIP code 54847 (Iron River, Bayfield County) is in USDA zone 4a: the coldest winter night averages −30 to −25 °F. The median last spring frost is May 24 and the first fall frost September 26.

Where ZIP 54847 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 24
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 Iron River, WI…

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 Iron River, WI

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 24median — 50% chance of a later frost
Safe for tender plantsJune 6only 10% chance of frost after
First fall frostSeptember 26median — 10% chance by Sep 9
Growing season124 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 9 and returns around October 6.

From the NOAA station Brule Rs, WI — 9 miles away, elevation 1,001 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 54847

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 12 – Apr 26
SpinachSow outdoors · Apr 12 – May 3
Broccoli, cabbageStart indoors · Mar 15 – Mar 29
Broccoli, cabbageTransplant · May 3 – May 17
Onion setsPlant outdoors · Apr 26 – May 10
PotatoesPlant outdoors · May 3 – May 17
LettuceSow outdoors · Apr 26 – May 10
Carrots, beetsSow outdoors · May 3 – May 17
TomatoesStart indoors · Mar 29 – Apr 12
TomatoesTransplant · May 31 – Jun 14
Peppers, eggplantStart indoors · Mar 15 – Mar 29
Peppers, eggplantTransplant · Jun 7 – Jun 21
BeansSow outdoors · May 31 – Jun 14
Sweet cornSow outdoors · May 31 – Jun 14
Cucumbers, squashSow outdoors · May 31 – Jun 14
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 24) 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 54847 came on Apr 30 — 5 days later than the 1991–2020 average (Apr 25).

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 Wisconsin

419 plants native to the lower 48 states, recorded in Wisconsin, and rated by the USDA to survive −30 °F or colder — the bottom of zone 4a. Each links to its USDA PLANTS profile.

Trees 45

American basswood100 ft · blooms late spring · low shade tolerance · to −46 °FAmerican beech80 ft · blooms mid spring · low shade tolerance · to −44 °FAmerican chestnut115 ft · blooms early summer · high shade tolerance · to −33 °FAmerican elm120 ft · blooms early spring · medium shade tolerance · to −46 °FAmerican sycamore100 ft · blooms spring · medium shade tolerance · to −34 °Farborvitae50 ft · blooms mid spring · medium shade tolerance · to −33 °F

Shrubs 71

alderleaf buckthorn3 ft · blooms late spring · low shade tolerance · to −33 °FAllegheny 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 hazelnut10 ft · blooms spring · medium shade tolerance · to −33 °FAmerican hornbeam30 ft · blooms mid spring · low shade tolerance · to −34 °F

Wildflowers & perennials 157

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °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 lotus3 ft · blooms mid summer · high shade tolerance · to −36 °FAmerican pokeweed7 ft · blooms mid summer · low shade tolerance · to −33 °F

Grasses 133

arctic brome3 ft · blooms early summer · low shade tolerance · to −33 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °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 °Fbig bluestem6 ft · blooms summer · high shade tolerance · to −46 °F

Vines 3

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 °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 Iron River, WI.

Soil in Iron River, WI

The soil mapped at the center of ZIP 54847 is Allendale — loamy fine sand, somewhat poorly drained.

TextureLoamy fine sanddrains and warms fast; dries out and needs more feeding
pH5.4strongly acidic; most vegetables like 6.0–7.0
DrainageSomewhat poorly drainedconsider raised beds
Organic matter3%moderate
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Allendale-Wakeley-Kinross complex, 0 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 54847; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Iron River, WI

Summer high78 °Faverage high, July
Winter low2 °Faverage low, January
Hot days4days a year at 90 °F or more
Freezing nights190nights a year at 32 °F or less
Growing degree days1,755base 50 °F — the season’s usable heat
Longest day15 h 50 mindaylight on June 21
Shortest day8 h 34 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation33.4 inper year, rain and melted snow

Average high and low, by month

−10°0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 20 °F, low 2 °F 20°2° JanFebruary: average high 26 °F, low 5 °F 26°5° FebMarch: average high 37 °F, low 18 °F 37°18° MarApril: average high 50 °F, low 29 °F 50°29° AprMay: average high 64 °F, low 40 °F 64°40° MayJune: average high 73 °F, low 50 °F 73°50° JunJuly: average high 78 °F, low 55 °F 78°55° JulAugust: average high 75 °F, low 54 °F 75°54° AugSeptember: average high 67 °F, low 46 °F 67°46° SepOctober: average high 53 °F, low 35 °F 53°35° OctNovember: average high 38 °F, low 23 °F 38°23° NovDecember: average high 25 °F, low 10 °F 25°10° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 1.06 in precipitation 1.1 JanFebruary: 1.04 in precipitation 1.0 FebMarch: 1.63 in precipitation 1.6 MarApril: 2.75 in precipitation 2.8 AprMay: 3.66 in precipitation 3.7 MayJune: 4.11 in precipitation 4.1 JunJuly: 4.38 in precipitation 4.4 JulAugust: 4.47 in precipitation 4.5 AugSeptember: 3.57 in precipitation 3.6 SepOctober: 3.28 in precipitation 3.3 OctNovember: 2.05 in precipitation 2.0 NovDecember: 1.44 in precipitation 1.4 Dec

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

Nearby ZIP codes

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

548204a
Brule, WI · 8 mi
548655a
Port Wing, WI · 12 mi
548544b
Maple, WI · 14 mi
548164b
Benoit, WI · 16 mi
548444b
Herbster, WI · 16 mi
548494a
Lake Nebagamon, WI · 16 mi
548564b
Mason, WI · 17 mi
548324a
Drummond, WI · 18 mi

Wisconsin planting zones →

Questions about 54847

What planting zone is ZIP code 54847?

ZIP code 54847 (Iron River, WI) 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 Iron River, WI?

The median last spring frost (32 °F) near 54847 is May 24; after June 6 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Brule Rs station.

When is the first frost in Iron River, WI?

The median first fall frost near 54847 is September 26, giving a median frost-free growing season of 124 days.

When should I plant tomatoes in 54847?

Start tomato seeds indoors around Mar 29 – Apr 12 and set transplants outside around May 31 – Jun 14, one to three weeks after the median last frost.

How much rain and snow does 54847 get?

About 33.4 inches of precipitation a year (NOAA 1991–2020 normals, Brule Rs station).

How hot do summers get in Iron River, WI?

The average high peaks at 78 °F in July, with about 4 days a year at 90 °F or more.

What kind of soil does 54847 have?

The USDA soil survey maps Allendale at the center of ZIP 54847: loamy fine sand, somewhat poorly drained, pH about 5.4 (strongly acidic).

Did spring come early in Iron River, WI in 2026?

Spring leaf-out near 54847 came on Apr 30 in 2026, 5 days later than the 1991–2020 average (Apr 25), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Iron River, WI?

Long-day onions: the longest day near 54847 is 15 h 50 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).