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

Planting zone for 55718 — Carlton, MN

ZIP code 55718 (Carlton, Carlton County) is in USDA zone 4a: the coldest winter night averages −30 to −25 °F. The median last spring frost is May 26 and the first fall frost September 23.

Where ZIP 55718 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 26

First frostSep 23

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 Carlton, 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 Carlton, MN

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 26median — 50% chance of a later frost

Safe for tender plantsJune 9only 10% chance of frost after

First fall frostSeptember 23median — 10% chance by Sep 9

Growing season118 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 12 and returns around October 3.

From the NOAA station Cloquet, MN — 6 miles away, elevation 1,266 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 55718

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 14 – Apr 28

SpinachSow outdoors · Apr 14 – May 5

Broccoli, cabbageStart indoors · Mar 17 – Mar 31

Broccoli, cabbageTransplant · May 5 – May 19

Onion setsPlant outdoors · Apr 28 – May 12

PotatoesPlant outdoors · May 5 – May 19

LettuceSow outdoors · Apr 28 – May 12

Carrots, beetsSow outdoors · May 5 – May 19

TomatoesStart indoors · Mar 31 – Apr 14

TomatoesTransplant · Jun 2 – Jun 16

Peppers, eggplantStart indoors · Mar 17 – Mar 31

Peppers, eggplantTransplant · Jun 9 – Jun 23

BeansSow outdoors · Jun 2 – Jun 16

Sweet cornSow outdoors · Jun 2 – Jun 16

Cucumbers, squashSow outdoors · Jun 2 – Jun 16

Fall lettuce, spinachSow outdoors · Jul 29 – Aug 12

GarlicPlant cloves · Sep 9 – Oct 14

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 26) and first fall frost (Sep 23) 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 55718 came on Apr 30 — 3 days later than the 1991–2020 average (Apr 27).

average
Apr 272026
Apr 30

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 Carlton, MN.

Soil in Carlton, MN

The soil mapped at the center of ZIP 55718 is Ahmeek — loam, well drained.

TextureLoama good balance for most vegetables

pH5.3strongly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter2%moderate

Hydrologic groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Ahmeek-Omega complex, 12 to 25 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 55718; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Carlton, MN

Summer high79 °Faverage high, July

Winter low2 °Faverage low, January

Hot days6days a year at 90 °F or more

Freezing nights191nights a year at 32 °F or less

Growing degree days1,680base 50 °F — the season’s usable heat

Longest day15 h 50 mindaylight on June 21

Shortest day8 h 33 mindaylight on December 21

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

Precipitation32.7 inper year, rain and melted snow

Snowfall71 inper year; 138 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: Cloquet, MN (6 mi away); precipitation: Cloquet, MN (6 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.

Minnesota planting zones →

Questions about 55718

What planting zone is ZIP code 55718?

ZIP code 55718 (Carlton, 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 Carlton, MN?

The median last spring frost (32 °F) near 55718 is May 26; after June 9 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Cloquet station.

When is the first frost in Carlton, MN?

The median first fall frost near 55718 is September 23, giving a median frost-free growing season of 118 days.

When should I plant tomatoes in 55718?

Start tomato seeds indoors around Mar 31 – Apr 14 and set transplants outside around Jun 2 – Jun 16, one to three weeks after the median last frost.

How much rain and snow does 55718 get?

About 32.7 inches of precipitation a year and 71 inches of snowfall (NOAA 1991–2020 normals, Cloquet station).

How hot do summers get in Carlton, MN?

The average high peaks at 79 °F in July, with about 6 days a year at 90 °F or more.

What kind of soil does 55718 have?

The USDA soil survey maps Ahmeek at the center of ZIP 55718: loam, well drained, pH about 5.3 (strongly acidic).

Did spring come early in Carlton, MN in 2026?

Spring leaf-out near 55718 came on Apr 30 in 2026, 3 days later than the 1991–2020 average (Apr 27), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Carlton, MN?

Long-day onions: the longest day near 55718 is 15 h 50 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).