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

Planting zone for 55797 — Wrenshall, MN

ZIP code 55797 (Wrenshall, Carlton County) is in USDA zone 4a: the coldest winter night averages −30 to −25 °F. The median last spring frost is June 1 and the first fall frost September 22.

Where ZIP 55797 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 frostJun 1

First frostSep 22

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 Wrenshall, 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 Wrenshall, MN

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostJune 1median — 50% chance of a later frost

Safe for tender plantsJune 14only 10% chance of frost after

First fall frostSeptember 22median — 10% chance by Sep 8

Growing season113 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 20 and returns around October 2.

From the NOAA station Foxboro, WI — 7 miles away, elevation 932 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 55797

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 20 – May 4

SpinachSow outdoors · Apr 20 – May 11

Broccoli, cabbageStart indoors · Mar 23 – Apr 6

Broccoli, cabbageTransplant · May 11 – May 25

Onion setsPlant outdoors · May 4 – May 18

PotatoesPlant outdoors · May 11 – May 25

LettuceSow outdoors · May 4 – May 18

Carrots, beetsSow outdoors · May 11 – May 25

TomatoesStart indoors · Apr 6 – Apr 20

TomatoesTransplant · Jun 8 – Jun 22

Peppers, eggplantStart indoors · Mar 23 – Apr 6

Peppers, eggplantTransplant · Jun 15 – Jun 29

BeansSow outdoors · Jun 8 – Jun 22

Sweet cornSow outdoors · Jun 8 – Jun 22

Cucumbers, squashSow outdoors · Jun 8 – Jun 22

Fall lettuce, spinachSow outdoors · Jul 28 – Aug 11

GarlicPlant cloves · Sep 8 – Oct 13

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 1) and first fall frost (Sep 22) 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 55797 came on Apr 30 — 4 days later than the 1991–2020 average (Apr 26).

average
Apr 262026
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 Wrenshall, MN.

Soil in Wrenshall, MN

The soil mapped at the center of ZIP 55797 is Ontonagon — silty clay, well drained.

TextureSilty clayholds water and nutrients; slow to drain and warm up

pH5.5moderately acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter2%moderate

Hydrologic groupDwater soaks in very slowly

Farmland classFarmland of statewide importanceUSDA classification

Map unit: Ontonagon silty clay, 2 to 12 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 55797; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Wrenshall, MN

Summer high78 °Faverage high, July

Winter low0 °Faverage low, January

Hot days4days a year at 90 °F or more

Freezing nights189nights a year at 32 °F or less

Growing degree days1,610base 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

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Foxboro, WI (7 mi away); precipitation: Pattison Ranger Staion, WI (12 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

4 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 55797

What planting zone is ZIP code 55797?

ZIP code 55797 (Wrenshall, 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 Wrenshall, MN?

The median last spring frost (32 °F) near 55797 is June 1; after June 14 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Foxboro station.

When is the first frost in Wrenshall, MN?

The median first fall frost near 55797 is September 22, giving a median frost-free growing season of 113 days.

When should I plant tomatoes in 55797?

Start tomato seeds indoors around Apr 6 – Apr 20 and set transplants outside around Jun 8 – Jun 22, one to three weeks after the median last frost.

How much rain and snow does 55797 get?

About 33.4 inches of precipitation a year (NOAA 1991–2020 normals, Pattison Ranger Staion station).

How hot do summers get in Wrenshall, MN?

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 55797 have?

The USDA soil survey maps Ontonagon at the center of ZIP 55797: silty clay, well drained, pH about 5.5 (moderately acidic).

Did spring come early in Wrenshall, MN in 2026?

Spring leaf-out near 55797 came on Apr 30 in 2026, 4 days later than the 1991–2020 average (Apr 26), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Wrenshall, MN?

Long-day onions: the longest day near 55797 is 15 h 50 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).