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

Planting zone for 56228 — Cosmos, MN

ZIP code 56228 (Cosmos, Meeker County) is in USDA zone 4b: the coldest winter night averages −25 to −20 °F. The median last spring frost is May 6 and the first fall frost October 2.

Where ZIP 56228 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 6
First frostOct 2
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 Cosmos, 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 Cosmos, MN

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 6median — 50% chance of a later frost
Safe for tender plantsMay 22only 10% chance of frost after
First fall frostOctober 2median — 10% chance by Sep 20
Growing season147 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 27 and returns around October 10.

From the NOAA station Litchfield, MN — 14 miles away, elevation 1,119 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 56228

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 25 – Apr 8
SpinachSow outdoors · Mar 25 – Apr 15
Broccoli, cabbageStart indoors · Feb 25 – Mar 11
Broccoli, cabbageTransplant · Apr 15 – Apr 29
Onion setsPlant outdoors · Apr 8 – Apr 22
PotatoesPlant outdoors · Apr 15 – Apr 29
LettuceSow outdoors · Apr 8 – Apr 22
Carrots, beetsSow outdoors · Apr 15 – Apr 29
TomatoesStart indoors · Mar 11 – Mar 25
TomatoesTransplant · May 13 – May 27
Peppers, eggplantStart indoors · Feb 25 – Mar 11
Peppers, eggplantTransplant · May 20 – Jun 3
BeansSow outdoors · May 13 – May 27
Sweet cornSow outdoors · May 13 – May 27
Cucumbers, squashSow outdoors · May 13 – May 27
Fall lettuce, spinachSow outdoors · Aug 7 – Aug 21
GarlicPlant cloves · Sep 18 – Oct 23
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 6) and first fall frost (Oct 2) 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 56228 came on Apr 16 — about the same time as the 1991–2020 average (Apr 18).

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 Cosmos, MN.

Soil in Cosmos, MN

The soil mapped at the center of ZIP 56228 is Kandiyohi — clay, somewhat poorly drained.

TextureClayholds water and nutrients; slow to drain and warm up
pH6.7neutral; most vegetables like 6.0–7.0
DrainageSomewhat poorly drainedconsider raised beds
Organic matter5.5%high
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classPrime farmland if drainedUSDA classification

Map unit: Kandiyohi clay, 0 to 2 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 56228; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Cosmos, MN

Summer high81 °Faverage high, July
Winter low0 °Faverage low, January
Hot days7days a year at 90 °F or more
Freezing nights168nights a year at 32 °F or less
Growing degree days2,343base 50 °F — the season’s usable heat
Longest day15 h 37 mindaylight on June 21
Shortest day8 h 46 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation29.8 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 20 °F, low 0 °F 20°0° JanFebruary: average high 25 °F, low 4 °F 25°4° FebMarch: average high 37 °F, low 17 °F 37°17° MarApril: average high 53 °F, low 32 °F 53°32° AprMay: average high 67 °F, low 45 °F 67°45° MayJune: average high 77 °F, low 56 °F 77°56° JunJuly: average high 81 °F, low 60 °F 81°60° JulAugust: average high 79 °F, low 58 °F 79°58° AugSeptember: average high 71 °F, low 48 °F 71°48° SepOctober: average high 56 °F, low 34 °F 56°34° OctNovember: average high 40 °F, low 21 °F 40°21° NovDecember: average high 26 °F, low 7 °F 26°7° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 0.78 in precipitation 0.8 JanFebruary: 0.78 in precipitation 0.8 FebMarch: 1.48 in precipitation 1.5 MarApril: 2.65 in precipitation 2.6 AprMay: 3.72 in precipitation 3.7 MayJune: 4.58 in precipitation 4.6 JunJuly: 3.81 in precipitation 3.8 JulAugust: 4.08 in precipitation 4.1 AugSeptember: 3.04 in precipitation 3.0 SepOctober: 2.56 in precipitation 2.6 OctNovember: 1.35 in precipitation 1.4 NovDecember: 0.95 in precipitation 0.9 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Litchfield, MN (14 mi away); precipitation: Litchfield, MN (14 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 4b.

562534b
Lake Lillian, MN · 9 mi
553554b
Litchfield, MN · 11 mi
553144b
Buffalo Lake, MN · 13 mi
562094b
Atwater, MN · 14 mi
553244b
Darwin, MN · 14 mi
553424b
Hector, MN · 15 mi
553504b
Hutchinson, MN · 15 mi
562434b
Grove City, MN · 15 mi

Minnesota planting zones →

Questions about 56228

What planting zone is ZIP code 56228?

ZIP code 56228 (Cosmos, 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 Cosmos, MN?

The median last spring frost (32 °F) near 56228 is May 6; after May 22 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Litchfield station.

When is the first frost in Cosmos, MN?

The median first fall frost near 56228 is October 2, giving a median frost-free growing season of 147 days.

When should I plant tomatoes in 56228?

Start tomato seeds indoors around Mar 11 – Mar 25 and set transplants outside around May 13 – May 27, one to three weeks after the median last frost.

How much rain and snow does 56228 get?

About 29.8 inches of precipitation a year (NOAA 1991–2020 normals, Litchfield station).

How hot do summers get in Cosmos, MN?

The average high peaks at 81 °F in July, with about 7 days a year at 90 °F or more.

What kind of soil does 56228 have?

The USDA soil survey maps Kandiyohi at the center of ZIP 56228: clay, somewhat poorly drained, pH about 6.7 (neutral).

Did spring come early in Cosmos, MN in 2026?

Spring leaf-out near 56228 came on Apr 16 in 2026, about the same as the 1991–2020 average (Apr 18), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Cosmos, MN?

Long-day onions: the longest day near 56228 is 15 h 37 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).