Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 55603 — Finland, MN

ZIP code 55603 (Finland, Lake County) is in USDA zone 4a: the coldest winter night averages −30 to −25 °F. The median last spring frost is May 15 and the first fall frost October 1.

Where ZIP 55603 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 15

First frostOct 1

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 Finland, 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 Finland, MN

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 15median — 50% chance of a later frost

Safe for tender plantsMay 31only 10% chance of frost after

First fall frostOctober 1median — 10% chance by Sep 17

Growing season137 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 2 and returns around October 10.

From the NOAA station Wolf Ridge Elc, MN — 7 miles away, elevation 1,401 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 55603

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 3 – Apr 17

SpinachSow outdoors · Apr 3 – Apr 24

Broccoli, cabbageStart indoors · Mar 6 – Mar 20

Broccoli, cabbageTransplant · Apr 24 – May 8

Onion setsPlant outdoors · Apr 17 – May 1

PotatoesPlant outdoors · Apr 24 – May 8

LettuceSow outdoors · Apr 17 – May 1

Carrots, beetsSow outdoors · Apr 24 – May 8

TomatoesStart indoors · Mar 20 – Apr 3

TomatoesTransplant · May 22 – Jun 5

Peppers, eggplantStart indoors · Mar 6 – Mar 20

Peppers, eggplantTransplant · May 29 – Jun 12

BeansSow outdoors · May 22 – Jun 5

Sweet cornSow outdoors · May 22 – Jun 5

Cucumbers, squashSow outdoors · May 22 – Jun 5

Fall lettuce, spinachSow outdoors · Aug 6 – Aug 20

GarlicPlant cloves · Sep 17 – Oct 22

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 15) and first fall frost (Oct 1) 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 55603 came on May 7 — 5 days later than the 1991–2020 average (May 2).

average
May 22026
May 7

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 Minnesota

445 plants native to the lower 48 states, recorded in Minnesota, and rated by the USDA to survive −30 °F or colder — the bottom of zone 4a. 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 Finland, MN.

Soil in Finland, MN

The soil mapped at the center of ZIP 55603 is Normanna — loam, moderately well drained.

TextureLoama good balance for most vegetables

pH5.6moderately acidic; most vegetables like 6.0–7.0

DrainageModerately well drainednatural drainage class

Organic matter5%high

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classFarmland of statewide importanceUSDA classification

Map unit: Normanna-Hermantown complex, 1 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 55603; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Finland, MN

Summer high76 °Faverage high, July

Winter low1 °Faverage low, January

Hot days3days a year at 90 °F or more

Freezing nights187nights a year at 32 °F or less

Growing degree days1,543base 50 °F — the season’s usable heat

Longest day15 h 59 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)

Precipitation32.5 inper year, rain and melted snow

Snowfall94 inper year; 149 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: Wolf Ridge Elc, MN (7 mi away); precipitation: Wolf Ridge Elc, MN (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

556134b

Schroeder, MN · 10 mi

556073b

Isabella, MN · 15 mi

556144a

Silver Bay, MN · 16 mi

556153b

Tofte, MN · 21 mi

556014a

Beaver Bay, MN · 23 mi

556123b

Lutsen, MN · 28 mi

556163b

Two Harbors, MN · 31 mi

557503b

Hoyt Lakes, MN · 35 mi

Minnesota planting zones →

Questions about 55603

What planting zone is ZIP code 55603?

ZIP code 55603 (Finland, MN) 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 Finland, MN?

The median last spring frost (32 °F) near 55603 is May 15; after May 31 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Wolf Ridge Elc station.

When is the first frost in Finland, MN?

The median first fall frost near 55603 is October 1, giving a median frost-free growing season of 137 days.

When should I plant tomatoes in 55603?

Start tomato seeds indoors around Mar 20 – Apr 3 and set transplants outside around May 22 – Jun 5, one to three weeks after the median last frost.

How much rain and snow does 55603 get?

About 32.5 inches of precipitation a year and 94 inches of snowfall (NOAA 1991–2020 normals, Wolf Ridge Elc station).

How hot do summers get in Finland, MN?

The average high peaks at 76 °F in July, with about 3 days a year at 90 °F or more.

What kind of soil does 55603 have?

The USDA soil survey maps Normanna at the center of ZIP 55603: loam, moderately well drained, pH about 5.6 (moderately acidic).

Did spring come early in Finland, MN in 2026?

Spring leaf-out near 55603 came on May 7 in 2026, 5 days later than the 1991–2020 average (May 2), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Finland, MN?

Long-day onions: the longest day near 55603 is 15 h 59 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).