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

Planting zone for 56037 — Good Thunder, MN

ZIP code 56037 (Good Thunder, Blue Earth County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is April 30 and the first fall frost October 9.

Where ZIP 56037 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.

Zone5a−20 to −15 °F
Coldest night−28.9 to −26.1 °C
Last frostApr 30
First frostOct 9
2012 zone4b

Was 4b 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 5a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Good Thunder, 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 Good Thunder, MN

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 30median — 50% chance of a later frost
Safe for tender plantsMay 12only 10% chance of frost after
First fall frostOctober 9median — 10% chance by Sep 25
Growing season161 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 19 and returns around October 20.

From the NOAA station Mankato, MN — 10 miles away, elevation 850 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 56037

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 19 – Apr 2
SpinachSow outdoors · Mar 19 – Apr 9
Broccoli, cabbageStart indoors · Feb 19 – Mar 5
Broccoli, cabbageTransplant · Apr 9 – Apr 23
Onion setsPlant outdoors · Apr 2 – Apr 16
PotatoesPlant outdoors · Apr 9 – Apr 23
LettuceSow outdoors · Apr 2 – Apr 16
Carrots, beetsSow outdoors · Apr 9 – Apr 23
TomatoesStart indoors · Mar 5 – Mar 19
TomatoesTransplant · May 7 – May 21
Peppers, eggplantStart indoors · Feb 19 – Mar 5
Peppers, eggplantTransplant · May 14 – May 28
BeansSow outdoors · May 7 – May 21
Sweet cornSow outdoors · May 7 – May 21
Cucumbers, squashSow outdoors · May 7 – May 21
Fall lettuce, spinachSow outdoors · Aug 14 – Aug 28
GarlicPlant cloves · Sep 25 – Oct 30
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 30) and first fall frost (Oct 9) 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 56037 came on Mar 30 — 16 days earlier than the 1991–2020 average (Apr 15).

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 5a in Minnesota

521 plants native to the lower 48 states, recorded in Minnesota, and rated by the USDA to survive −20 °F or colder — the bottom of zone 5a. 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 92

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 201

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 164

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 5

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 °Fsummer grape30 ft · blooms late spring · low shade tolerance · to −23 °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 Good Thunder, MN.

Soil in Good Thunder, MN

The soil mapped at the center of ZIP 56037 is Minnetonka — silty clay loam, poorly drained.

TextureSilty clay loamholds water and nutrients; slow to drain and warm up
pH6.5neutral; most vegetables like 6.0–7.0
DrainagePoorly drainedconsider raised beds
Organic matter6%high
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classPrime farmland if drainedUSDA classification

Map unit: Minnetonka silty clay loam.

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 56037; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Good Thunder, MN

Summer high82 °Faverage high, July
Winter low6 °Faverage low, January
Hot days10days a year at 90 °F or more
Freezing nights161nights a year at 32 °F or less
Growing degree days2,657base 50 °F — the season’s usable heat
Longest day15 h 29 mindaylight on June 21
Shortest day8 h 53 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation33.9 inper year, rain and melted snow
Snowfall39 inper year; 82 days with snow on the ground

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 24 °F, low 6 °F 24°6° JanFebruary: average high 29 °F, low 9 °F 29°9° FebMarch: average high 41 °F, low 22 °F 41°22° MarApril: average high 57 °F, low 34 °F 57°34° AprMay: average high 69 °F, low 47 °F 69°47° MayJune: average high 79 °F, low 58 °F 79°58° JunJuly: average high 82 °F, low 62 °F 82°62° JulAugust: average high 80 °F, low 59 °F 80°59° AugSeptember: average high 74 °F, low 50 °F 74°50° SepOctober: average high 60 °F, low 37 °F 60°37° OctNovember: average high 43 °F, low 25 °F 43°25° NovDecember: average high 29 °F, low 13 °F 29°13° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″6″January: 0.99 in precipitation, 8.2 in snowfall 1.0❄8 JanFebruary: 0.84 in precipitation, 6.9 in snowfall 0.8❄7 FebMarch: 1.88 in precipitation, 7.4 in snowfall 1.9❄7 MarApril: 3.31 in precipitation, 1.6 in snowfall 3.3❄2 AprMay: 4.20 in precipitation 4.2 MayJune: 5.64 in precipitation 5.6 JunJuly: 4.26 in precipitation 4.3 JulAugust: 4.31 in precipitation 4.3 AugSeptember: 3.30 in precipitation 3.3 SepOctober: 2.37 in precipitation, 0.1 in snowfall 2.4 OctNovember: 1.65 in precipitation, 5.9 in snowfall 1.6❄6 NovDecember: 1.13 in precipitation, 8.6 in snowfall 1.1❄9 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Mankato, MN (10 mi away); precipitation: Mankato, MN (10 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5a.

560345a
Garden City, MN · 7 mi
560655a
Mapleton, MN · 8 mi
560015a
Mankato, MN · 9 mi
560805a
Saint Clair, MN · 10 mi
560905a
Vernon Center, MN · 10 mi
560025a
Mankato, MN · 10 mi
560105a
Amboy, MN · 11 mi
560555a
Lake Crystal, MN · 13 mi

Minnesota planting zones →

Questions about 56037

What planting zone is ZIP code 56037?

ZIP code 56037 (Good Thunder, MN) is in USDA hardiness zone 5a on the 2023 map: the coldest night of an average winter reaches −20 to −15 °F (−28.9 to −26.1 °C).

When is the last frost in Good Thunder, MN?

The median last spring frost (32 °F) near 56037 is April 30; after May 12 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Mankato station.

When is the first frost in Good Thunder, MN?

The median first fall frost near 56037 is October 9, giving a median frost-free growing season of 161 days.

When should I plant tomatoes in 56037?

Start tomato seeds indoors around Mar 5 – Mar 19 and set transplants outside around May 7 – May 21, one to three weeks after the median last frost.

How much rain and snow does 56037 get?

About 33.9 inches of precipitation a year and 39 inches of snowfall (NOAA 1991–2020 normals, Mankato station).

How hot do summers get in Good Thunder, MN?

The average high peaks at 82 °F in July, with about 10 days a year at 90 °F or more.

What kind of soil does 56037 have?

The USDA soil survey maps Minnetonka at the center of ZIP 56037: silty clay loam, poorly drained, pH about 6.5 (neutral).

Did spring come early in Good Thunder, MN in 2026?

Spring leaf-out near 56037 came on Mar 30 in 2026, 16 days earlier than the 1991–2020 average (Apr 15), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Good Thunder, MN?

Long-day onions: the longest day near 56037 is 15 h 29 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 56037 change?

Yes. The 2012 USDA map put 56037 in zone 4b; the 2023 map puts it in zone 5a. The newer map uses 1991–2020 data and more weather stations.