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

Planting zone for 55723 — Cook, MN

ZIP code 55723 (Cook, St. Louis County) is in USDA zone 3b: the coldest winter night averages −35 to −30 °F. The median last spring frost is June 1 and the first fall frost September 15.

Where ZIP 55723 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.

Zone3b−35 to −30 °F

Coldest night−37.2 to −34.4 °C

Last frostJun 1

First frostSep 15

2012 zone3a

Was 3a on the 2012 map — half a zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 3b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Cook, 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 Cook, 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 18only 10% chance of frost after

First fall frostSeptember 15median — 10% chance by Aug 27

Growing season104 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 20 and returns around September 27.

From the NOAA station Celina 2e, MN — 8 miles away, elevation 1,286 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 55723

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 21 – Aug 4

GarlicPlant cloves · Sep 1 – Oct 6

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jun 1) and first fall frost (Sep 15) 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 55723 came on Apr 29 — about the same time as the 1991–2020 average (Apr 29).

average
Apr 292026
Apr 29

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 3b in Minnesota

287 plants native to the lower 48 states, recorded in Minnesota, and rated by the USDA to survive −35 °F or colder — the bottom of zone 3b. 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 Cook, MN.

Soil in Cook, MN

The soil mapped at the center of ZIP 55723 is Daisybay — peat, very poorly drained.

TexturePeattop layer

DrainageVery poorly drainedconsider raised beds

Organic matter95%high

Hydrologic groupDwater soaks in very slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Daisybay-Greenwood complex, 0 to 1 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 55723; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Cook, MN

Summer high77 °Faverage high, July

Winter low−7 °Faverage low, January

Hot days1days a year at 90 °F or more

Freezing nights212nights a year at 32 °F or less

Growing degree days1,416base 50 °F — the season’s usable heat

Longest day16 h 01 mindaylight on June 21

Shortest day8 h 23 mindaylight on December 21

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

Precipitation26 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: Celina 2e, MN (8 mi away); precipitation: Orr 3e, MN (15 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 3b.

557033b

Angora, MN · 9 mi

557813b

Side Lake, MN · 15 mi

Nett Lake, MN · 22 mi

557683b

Mountain Iron, MN · 23 mi

557583b

Kinney, MN · 24 mi

Minnesota planting zones →

Questions about 55723

What planting zone is ZIP code 55723?

ZIP code 55723 (Cook, MN) is in USDA hardiness zone 3b on the 2023 map: the coldest night of an average winter reaches −35 to −30 °F (−37.2 to −34.4 °C).

When is the last frost in Cook, MN?

The median last spring frost (32 °F) near 55723 is June 1; after June 18 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Celina 2e station.

When is the first frost in Cook, MN?

The median first fall frost near 55723 is September 15, giving a median frost-free growing season of 104 days.

When should I plant tomatoes in 55723?

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 55723 get?

About 26 inches of precipitation a year (NOAA 1991–2020 normals, Orr 3e station).

How hot do summers get in Cook, 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 55723 have?

The USDA soil survey maps Daisybay at the center of ZIP 55723: peat, very poorly drained.

Did spring come early in Cook, MN in 2026?

Spring leaf-out near 55723 came on Apr 29 in 2026, about the same as the 1991–2020 average (Apr 29), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Cook, MN?

Long-day onions: the longest day near 55723 is 16 h 01 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 55723 change?

Yes. The 2012 USDA map put 55723 in zone 3a; the 2023 map puts it in zone 3b. The newer map uses 1991–2020 data and more weather stations.