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

Planting zone for 55804 — Duluth, MN

ZIP code 55804 (Duluth, St. Louis County) is in USDA zone 4b: the coldest winter night averages −25 to −20 °F. The median last spring frost is May 21 and the first fall frost September 27.

Where ZIP 55804 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.

Zone4b−25 to −20 °F
Coldest night−31.7 to −28.9 °C
Last frostMay 21
First frostSep 27
2012 zone4b

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 4b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Duluth, 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 Duluth, MN

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 3only 10% chance of frost after
First fall frostSeptember 27median — 10% chance by Sep 13
Growing season129 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 7 and returns around October 7.

From the NOAA station Island Lake 4e, MN — 9 miles away, elevation 1,411 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 55804

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 · Aug 2 – Aug 16
GarlicPlant cloves · Sep 13 – Oct 18
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 21) and first fall frost (Sep 27) 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 55804 came on May 2 — about the same time as the 1991–2020 average (May 2).

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 4b in Minnesota

497 plants native to the lower 48 states, recorded in Minnesota, and rated by the USDA to survive −25 °F or colder — the bottom of zone 4b. Each links to its USDA PLANTS profile.

Trees 47

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 °Farborvitae50 ft · blooms mid spring · medium shade tolerance · to −33 °Fbalsam fir60 ft · blooms mid summer · low shade tolerance · to −43 °Fbalsam poplar80 ft · blooms late spring · high shade tolerance · to −79 °F

Shrubs 88

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 190

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine bistort1 ft · blooms mid spring · high 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 °F

Grasses 156

alkali cordgrass3 ft · blooms late summer · high shade tolerance · to −38 °FAmerican beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °Farctic brome3 ft · blooms early summer · low shade tolerance · to −33 °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 °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 °FVirginia creeper1 ft · blooms late spring · medium shade tolerance · to −28 °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 Duluth, MN.

Soil in Duluth, MN

The soil mapped at the center of ZIP 55804 is Badriver — silt loam, somewhat poorly drained.

TextureSilt loama good balance for most vegetables
pH5.6moderately acidic; most vegetables like 6.0–7.0
DrainageSomewhat poorly drainedconsider raised beds
Organic matter5%high
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classFarmland of statewide importanceUSDA classification

Map unit: Badriver complex, 0 to 3 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 55804; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Duluth, MN

Summer high77 °Faverage high, July
Winter low−2 °Faverage low, January
Hot days1days a year at 90 °F or more
Freezing nights190nights a year at 32 °F or less
Growing degree days1,659base 50 °F — the season’s usable heat
Longest day15 h 53 mindaylight on June 21
Shortest day8 h 31 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation30.7 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 17 °F, low -2 °F 17°−2° JanFebruary: average high 23 °F, low 1 °F 23°1° FebMarch: average high 36 °F, low 15 °F 36°15° MarApril: average high 48 °F, low 28 °F 48°28° AprMay: average high 63 °F, low 40 °F 63°40° MayJune: average high 72 °F, low 50 °F 72°50° JunJuly: average high 77 °F, low 55 °F 77°55° JulAugust: average high 75 °F, low 54 °F 75°54° AugSeptember: average high 66 °F, low 46 °F 66°46° SepOctober: average high 51 °F, low 34 °F 51°34° OctNovember: average high 35 °F, low 21 °F 35°21° NovDecember: average high 23 °F, low 7 °F 23°7° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 1.00 in precipitation 1.0 JanFebruary: 0.98 in precipitation 1.0 FebMarch: 1.41 in precipitation 1.4 MarApril: 2.36 in precipitation 2.4 AprMay: 3.40 in precipitation 3.4 MayJune: 4.40 in precipitation 4.4 JunJuly: 4.08 in precipitation 4.1 JulAugust: 3.46 in precipitation 3.5 AugSeptember: 3.49 in precipitation 3.5 SepOctober: 2.91 in precipitation 2.9 OctNovember: 1.76 in precipitation 1.8 NovDecember: 1.42 in precipitation 1.4 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Island Lake 4e, MN (9 mi away); precipitation: Island Lake 4e, MN (9 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

556094b
Knife River, MN · 7 mi
558034a
Duluth, MN · 10 mi
558124b
Duluth, MN · 11 mi
558054b
Duluth, MN · 12 mi
558154b
Duluth, MN · 13 mi
558165a
Duluth, MN · 13 mi
558025a
Duluth, MN · 13 mi
558144b
Duluth, MN · 14 mi

All 13 ZIP codes in Duluth → · Minnesota planting zones →

Questions about 55804

What planting zone is ZIP code 55804?

ZIP code 55804 (Duluth, MN) is in USDA hardiness zone 4b on the 2023 map: the coldest night of an average winter reaches −25 to −20 °F (−31.7 to −28.9 °C).

When is the last frost in Duluth, MN?

The median last spring frost (32 °F) near 55804 is May 21; after June 3 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Island Lake 4e station.

When is the first frost in Duluth, MN?

The median first fall frost near 55804 is September 27, giving a median frost-free growing season of 129 days.

When should I plant tomatoes in 55804?

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 55804 get?

About 30.7 inches of precipitation a year (NOAA 1991–2020 normals, Island Lake 4e station).

How hot do summers get in Duluth, MN?

The average high peaks at 77 °F in July, with about 1 days a year at 90 °F or more.

What kind of soil does 55804 have?

The USDA soil survey maps Badriver at the center of ZIP 55804: silt loam, somewhat poorly drained, pH about 5.6 (moderately acidic).

Did spring come early in Duluth, MN in 2026?

Spring leaf-out near 55804 came on May 2 in 2026, about the same as the 1991–2020 average (May 2), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Duluth, MN?

Long-day onions: the longest day near 55804 is 15 h 53 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).