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

Planting zone for 55972 — Saint Charles, MN

ZIP code 55972 (Saint Charles, Winona County) is in USDA zone 4b: the coldest winter night averages −25 to −20 °F. The median last spring frost is April 23 and the first fall frost October 16.

Where ZIP 55972 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 frostApr 23
First frostOct 16
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 Saint Charles, 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 Saint Charles, MN

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 23median — 50% chance of a later frost
Safe for tender plantsMay 6only 10% chance of frost after
First fall frostOctober 16median — 10% chance by Oct 2
Growing season175 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 13 and returns around October 25.

From the NOAA station Minnesota City Dam 5, MN — 17 miles away, elevation 669 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 55972

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 12 – Mar 26
SpinachSow outdoors · Mar 12 – Apr 2
Broccoli, cabbageStart indoors · Feb 12 – Feb 26
Broccoli, cabbageTransplant · Apr 2 – Apr 16
Onion setsPlant outdoors · Mar 26 – Apr 9
PotatoesPlant outdoors · Apr 2 – Apr 16
LettuceSow outdoors · Mar 26 – Apr 9
Carrots, beetsSow outdoors · Apr 2 – Apr 16
TomatoesStart indoors · Feb 26 – Mar 12
TomatoesTransplant · Apr 30 – May 14
Peppers, eggplantStart indoors · Feb 12 – Feb 26
Peppers, eggplantTransplant · May 7 – May 21
BeansSow outdoors · Apr 30 – May 14
Sweet cornSow outdoors · Apr 30 – May 14
Cucumbers, squashSow outdoors · Apr 30 – May 14
Fall lettuce, spinachSow outdoors · Aug 21 – Sep 4
GarlicPlant cloves · Oct 2 – Nov 6
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 23) and first fall frost (Oct 16) 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 55972 came on Mar 30 — 18 days earlier than the 1991–2020 average (Apr 17).

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 Saint Charles, MN.

Soil in Saint Charles, MN

The soil mapped at the center of ZIP 55972 is Downs — silt loam, well drained.

TextureSilt loama good balance for most vegetables
pH6.2slightly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2.5%moderate
Hydrologic groupCwater soaks in slowly
Farmland classFarmland of statewide importanceUSDA classification

Map unit: Downs silt loam, 6 to 12 percent slopes, moderately eroded.

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 55972; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Saint Charles, MN

Summer high83 °Faverage high, July
Winter low8 °Faverage low, January
Hot days14days a year at 90 °F or more
Freezing nights140nights a year at 32 °F or less
Growing degree days2,823base 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)
Precipitation37.1 inper year, rain and melted snow
Snowfall45 inper year; 95 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 23 °F, low 8 °F 23°8° JanFebruary: average high 29 °F, low 11 °F 29°11° FebMarch: average high 42 °F, low 25 °F 42°25° MarApril: average high 56 °F, low 37 °F 56°37° AprMay: average high 69 °F, low 50 °F 69°50° MayJune: average high 79 °F, low 59 °F 79°59° JunJuly: average high 83 °F, low 64 °F 83°64° JulAugust: average high 80 °F, low 62 °F 80°62° AugSeptember: average high 71 °F, low 54 °F 71°54° SepOctober: average high 57 °F, low 41 °F 57°41° OctNovember: average high 41 °F, low 28 °F 41°28° NovDecember: average high 28 °F, low 15 °F 28°15° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″6″January: 1.04 in precipitation, 8.6 in snowfall 1.0❄9 JanFebruary: 1.15 in precipitation, 11 in snowfall 1.1❄11 FebMarch: 1.86 in precipitation, 8.2 in snowfall 1.9❄8 MarApril: 3.72 in precipitation, 2.9 in snowfall 3.7❄3 AprMay: 4.82 in precipitation, 0.6 in snowfall 4.8❄1 MayJune: 5.42 in precipitation 5.4 JunJuly: 4.53 in precipitation 4.5 JulAugust: 5.18 in precipitation 5.2 AugSeptember: 3.62 in precipitation 3.6 SepOctober: 2.53 in precipitation, 0.4 in snowfall 2.5 OctNovember: 1.87 in precipitation, 2.2 in snowfall 1.9❄2 NovDecember: 1.32 in precipitation, 11 in snowfall 1.3❄11 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Minnesota City Dam 5, MN (17 mi away); precipitation: Altura 5w, MN (5 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 4b.

559294b
Dover, MN · 5 mi
559794b
Utica, MN · 7 mi
559104b
Altura, MN · 10 mi
559694b
Rollingstone, MN · 11 mi
559344b
Eyota, MN · 11 mi
559524b
Lewiston, MN · 11 mi
559234b
Chatfield, MN · 12 mi
559644b
Plainview, MN · 13 mi

Minnesota planting zones →

Questions about 55972

What planting zone is ZIP code 55972?

ZIP code 55972 (Saint Charles, 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 Saint Charles, MN?

The median last spring frost (32 °F) near 55972 is April 23; after May 6 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Minnesota City Dam 5 station.

When is the first frost in Saint Charles, MN?

The median first fall frost near 55972 is October 16, giving a median frost-free growing season of 175 days.

When should I plant tomatoes in 55972?

Start tomato seeds indoors around Feb 26 – Mar 12 and set transplants outside around Apr 30 – May 14, one to three weeks after the median last frost.

How much rain and snow does 55972 get?

About 37.1 inches of precipitation a year and 45 inches of snowfall (NOAA 1991–2020 normals, Altura 5w station).

How hot do summers get in Saint Charles, MN?

The average high peaks at 83 °F in July, with about 14 days a year at 90 °F or more.

What kind of soil does 55972 have?

The USDA soil survey maps Downs at the center of ZIP 55972: silt loam, well drained, pH about 6.2 (slightly acidic).

Did spring come early in Saint Charles, MN in 2026?

Spring leaf-out near 55972 came on Mar 30 in 2026, 18 days earlier than the 1991–2020 average (Apr 17), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Saint Charles, MN?

Long-day onions: the longest day near 55972 is 15 h 29 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).