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

Planting zone for 54648 — Norwalk, WI

ZIP code 54648 (Norwalk, Monroe County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 6 and the first fall frost October 3.

Where ZIP 54648 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 frostMay 6
First frostOct 3
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 Norwalk, WI…

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 Norwalk, WI

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 20only 10% chance of frost after
First fall frostOctober 3median — 10% chance by Sep 20
Growing season150 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 27 and returns around October 13.

From the NOAA station Cashton 3nnw, WI — 9 miles away, elevation 938 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 54648

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 8 – Aug 22
GarlicPlant cloves · Sep 19 – Oct 24
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 6) and first fall frost (Oct 3) 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 54648 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 Wisconsin

510 plants native to the lower 48 states, recorded in Wisconsin, and rated by the USDA to survive −20 °F or colder — the bottom of zone 5a. Each links to its USDA PLANTS profile.

Trees 48

American basswood100 ft · blooms late spring · low shade tolerance · to −46 °FAmerican beech80 ft · blooms mid spring · low shade tolerance · to −44 °FAmerican chestnut115 ft · blooms early summer · high shade tolerance · to −33 °FAmerican elm120 ft · blooms early spring · medium shade tolerance · to −46 °FAmerican sycamore100 ft · blooms spring · medium shade tolerance · to −34 °Farborvitae50 ft · blooms mid spring · medium shade tolerance · to −33 °F

Shrubs 93

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 191

alkali buttercup1 ft · blooms late spring · low 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 °FAmerican pokeweed7 ft · blooms mid summer · low shade tolerance · to −33 °F

Grasses 158

American 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 °Fbeaked sedge4 ft · blooms late spring · low shade tolerance · to −38 °Fbeaked spikerush3 ft · blooms late spring · high shade tolerance · to −28 °FBebb's sedge3 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 Norwalk, WI.

Soil in Norwalk, WI

The soil mapped at the center of ZIP 54648 is Council — moderately decomposed plant material, well drained.

TextureModerately decomposed plant materialtop layer
pH3.5strongly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter80%high
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Council-Elevasil-Norden complex, 20 to 45 percent slopes, rocky.

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 54648; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Norwalk, WI

Summer high80 °Faverage high, July
Winter low8 °Faverage low, January
Hot days2days a year at 90 °F or more
Freezing nights162nights a year at 32 °F or less
Growing degree days2,319base 50 °F — the season’s usable heat
Longest day15 h 28 mindaylight on June 21
Shortest day8 h 54 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation36.7 inper year, rain and melted snow

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 26 °F, low 8 °F 26°8° JanFebruary: average high 31 °F, low 11 °F 31°11° FebMarch: average high 42 °F, low 21 °F 42°21° MarApril: average high 56 °F, low 34 °F 56°34° AprMay: average high 68 °F, low 45 °F 68°45° MayJune: average high 77 °F, low 55 °F 77°55° JunJuly: average high 80 °F, low 59 °F 80°59° JulAugust: average high 79 °F, low 57 °F 79°57° AugSeptember: average high 72 °F, low 48 °F 72°48° SepOctober: average high 59 °F, low 36 °F 59°36° OctNovember: average high 44 °F, low 26 °F 44°26° NovDecember: average high 31 °F, low 15 °F 31°15° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 1.18 in precipitation 1.2 JanFebruary: 1.00 in precipitation 1.0 FebMarch: 1.84 in precipitation 1.8 MarApril: 3.82 in precipitation 3.8 AprMay: 4.67 in precipitation 4.7 MayJune: 5.41 in precipitation 5.4 JunJuly: 4.39 in precipitation 4.4 JulAugust: 4.41 in precipitation 4.4 AugSeptember: 3.84 in precipitation 3.8 SepOctober: 2.73 in precipitation 2.7 OctNovember: 1.88 in precipitation 1.9 NovDecember: 1.50 in precipitation 1.5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Cashton 3nnw, WI (9 mi away); precipitation: Cashton 3nnw, WI (9 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.

546705a
Wilton, WI · 8 mi
546514b
Ontario, WI · 9 mi
546195a
Cashton, WI · 9 mi
546385a
Kendall, WI · 12 mi
546624b
Tunnel City, WI · 12 mi
546604b
Tomah, WI · 12 mi
546564b
Sparta, WI · 14 mi
546535a
Rockland, WI · 15 mi

Wisconsin planting zones →

Questions about 54648

What planting zone is ZIP code 54648?

ZIP code 54648 (Norwalk, WI) 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 Norwalk, WI?

The median last spring frost (32 °F) near 54648 is May 6; after May 20 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Cashton 3nnw station.

When is the first frost in Norwalk, WI?

The median first fall frost near 54648 is October 3, giving a median frost-free growing season of 150 days.

When should I plant tomatoes in 54648?

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 54648 get?

About 36.7 inches of precipitation a year (NOAA 1991–2020 normals, Cashton 3nnw station).

How hot do summers get in Norwalk, WI?

The average high peaks at 80 °F in July, with about 2 days a year at 90 °F or more.

What kind of soil does 54648 have?

The USDA soil survey maps Council at the center of ZIP 54648: moderately decomposed plant material, well drained, pH about 3.5 (strongly acidic).

Did spring come early in Norwalk, WI in 2026?

Spring leaf-out near 54648 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 Norwalk, WI?

Long-day onions: the longest day near 54648 is 15 h 28 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 54648 change?

Yes. The 2012 USDA map put 54648 in zone 4b; the 2023 map puts it in zone 5a. The newer map uses 1991–2020 data and more weather stations.