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

Planting zone for 54985 — Winnebago, WI

ZIP code 54985 (Winnebago, Winnebago County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is April 24 and the first fall frost October 20.

Where ZIP 54985 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.

Zone5b−15 to −10 °F

Coldest night−26.1 to −23.3 °C

Last frostApr 24

First frostOct 20

2012 zone5a

Was 5a 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 5b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Winnebago, 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 Winnebago, WI

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostApril 24median — 50% chance of a later frost

Safe for tender plantsMay 8only 10% chance of frost after

First fall frostOctober 20median — 10% chance by Oct 4

Growing season178 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 13 and returns around October 31.

From the NOAA station Oshkosh, WI — 4 miles away, elevation 751 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 54985

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 13 – Mar 27

SpinachSow outdoors · Mar 13 – Apr 3

Broccoli, cabbageStart indoors · Feb 13 – Feb 27

Broccoli, cabbageTransplant · Apr 3 – Apr 17

Onion setsPlant outdoors · Mar 27 – Apr 10

PotatoesPlant outdoors · Apr 3 – Apr 17

LettuceSow outdoors · Mar 27 – Apr 10

Carrots, beetsSow outdoors · Apr 3 – Apr 17

TomatoesStart indoors · Feb 27 – Mar 13

TomatoesTransplant · May 1 – May 15

Peppers, eggplantStart indoors · Feb 13 – Feb 27

Peppers, eggplantTransplant · May 8 – May 22

BeansSow outdoors · May 1 – May 15

Sweet cornSow outdoors · May 1 – May 15

Cucumbers, squashSow outdoors · May 1 – May 15

Fall lettuce, spinachSow outdoors · Aug 25 – Sep 8

GarlicPlant cloves · Oct 6 – Nov 10

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 24) and first fall frost (Oct 20) 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 54985 came on Apr 11 — 6 days earlier than the 1991–2020 average (Apr 17).

average
Apr 172026
Apr 11

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).

Soil in Winnebago, WI

The soil mapped at the center of ZIP 54985 is Manawa — silty clay loam, somewhat poorly drained.

TextureSilty clay loamholds water and nutrients; slow to drain and warm up

pH7.0neutral; most vegetables like 6.0–7.0

DrainageSomewhat poorly drainedconsider raised beds

Organic matter3%moderate

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classPrime farmland if drainedUSDA classification

Map unit: Manawa silty clay loam, 0 to 3 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 54985; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Winnebago, WI

Summer high82 °Faverage high, July

Winter low10 °Faverage low, January

Hot days8days a year at 90 °F or more

Freezing nights143nights a year at 32 °F or less

Growing degree days2,699base 50 °F — the season’s usable heat

Longest day15 h 30 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)

Precipitation33.3 inper year, rain and melted snow

Snowfall39 inper year; 77 days with snow on the ground

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Oshkosh, WI (4 mi away); precipitation: Oshkosh, WI (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5b.

Butte Des Morts, WI · 7 mi

Wisconsin planting zones →

Questions about 54985

What planting zone is ZIP code 54985?

ZIP code 54985 (Winnebago, WI) is in USDA hardiness zone 5b on the 2023 map: the coldest night of an average winter reaches −15 to −10 °F (−26.1 to −23.3 °C).

When is the last frost in Winnebago, WI?

The median last spring frost (32 °F) near 54985 is April 24; after May 8 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Oshkosh station.

When is the first frost in Winnebago, WI?

The median first fall frost near 54985 is October 20, giving a median frost-free growing season of 178 days.

When should I plant tomatoes in 54985?

Start tomato seeds indoors around Feb 27 – Mar 13 and set transplants outside around May 1 – May 15, one to three weeks after the median last frost.

How much rain and snow does 54985 get?

About 33.3 inches of precipitation a year and 39 inches of snowfall (NOAA 1991–2020 normals, Oshkosh station).

How hot do summers get in Winnebago, WI?

The average high peaks at 82 °F in July, with about 8 days a year at 90 °F or more.

What kind of soil does 54985 have?

The USDA soil survey maps Manawa at the center of ZIP 54985: silty clay loam, somewhat poorly drained, pH about 7.0 (neutral).

Did spring come early in Winnebago, WI in 2026?

Spring leaf-out near 54985 came on Apr 11 in 2026, 6 days earlier than the 1991–2020 average (Apr 17), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Winnebago, WI?

Long-day onions: the longest day near 54985 is 15 h 30 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 54985 change?

Yes. The 2012 USDA map put 54985 in zone 5a; the 2023 map puts it in zone 5b. The newer map uses 1991–2020 data and more weather stations.