Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 30, 2026

Planting zone for 54490 — Westboro, WI

ZIP code 54490 (Westboro, Taylor County) is in USDA zone 4a: the coldest winter night averages −30 to −25 °F. The median last spring frost is May 11 and the first fall frost October 1.

Where ZIP 54490 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.

Zone4a−30 to −25 °F

Coldest night−34.4 to −31.7 °C

Last frostMay 11

First frostOct 1

2012 zone3b

Was 3b 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 4a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Westboro, 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 Westboro, WI

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 11median — 50% chance of a later frost

Safe for tender plantsMay 26only 10% chance of frost after

First fall frostOctober 1median — 10% chance by Sep 17

Growing season141 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 1 and returns around October 11.

From the NOAA station Medford, WI — 14 miles away, elevation 1,470 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 54490

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 30 – Apr 13

SpinachSow outdoors · Mar 30 – Apr 20

Broccoli, cabbageStart indoors · Mar 2 – Mar 16

Broccoli, cabbageTransplant · Apr 20 – May 4

Onion setsPlant outdoors · Apr 13 – Apr 27

PotatoesPlant outdoors · Apr 20 – May 4

LettuceSow outdoors · Apr 13 – Apr 27

Carrots, beetsSow outdoors · Apr 20 – May 4

TomatoesStart indoors · Mar 16 – Mar 30

TomatoesTransplant · May 18 – Jun 1

Peppers, eggplantStart indoors · Mar 2 – Mar 16

Peppers, eggplantTransplant · May 25 – Jun 8

BeansSow outdoors · May 18 – Jun 1

Sweet cornSow outdoors · May 18 – Jun 1

Cucumbers, squashSow outdoors · May 18 – Jun 1

Fall lettuce, spinachSow outdoors · Aug 6 – Aug 20

GarlicPlant cloves · Sep 17 – Oct 22

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 11) and first fall frost (Oct 1) 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 54490 came on Apr 16 — 6 days earlier than the 1991–2020 average (Apr 22).

average
Apr 222026
Apr 16

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 4a in Wisconsin

419 plants native to the lower 48 states, recorded in Wisconsin, and rated by the USDA to survive −30 °F or colder — the bottom of zone 4a. Each links to its USDA PLANTS profile.

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 Westboro, WI.

Soil in Westboro, WI

The soil mapped at the center of ZIP 54490 is Magnor — silt loam, somewhat poorly drained.

TextureSilt loama good balance for most vegetables

pH5.0strongly acidic; most vegetables like 6.0–7.0

DrainageSomewhat poorly drainedconsider raised beds

Organic matter8%high

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classPrime farmland if drainedUSDA classification

Map unit: Magnor-Freeon complex, 0 to 6 percent slopes, very stony.

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 54490; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Westboro, WI

Summer high79 °Faverage high, July

Winter low2 °Faverage low, January

Hot days3days a year at 90 °F or more

Freezing nights177nights a year at 32 °F or less

Growing degree days2,038base 50 °F — the season’s usable heat

Longest day15 h 40 mindaylight on June 21

Shortest day8 h 43 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation34.2 inper year, rain and melted snow

Snowfall57 inper year; 109 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: Medford, WI (14 mi away); precipitation: Medford, WI (14 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

1 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

Stetsonville, WI · 20 mi

545304a

Hawkins, WI · 20 mi

Wisconsin planting zones →

Questions about 54490

What planting zone is ZIP code 54490?

ZIP code 54490 (Westboro, WI) is in USDA hardiness zone 4a on the 2023 map: the coldest night of an average winter reaches −30 to −25 °F (−34.4 to −31.7 °C).

When is the last frost in Westboro, WI?

The median last spring frost (32 °F) near 54490 is May 11; after May 26 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Medford station.

When is the first frost in Westboro, WI?

The median first fall frost near 54490 is October 1, giving a median frost-free growing season of 141 days.

When should I plant tomatoes in 54490?

Start tomato seeds indoors around Mar 16 – Mar 30 and set transplants outside around May 18 – Jun 1, one to three weeks after the median last frost.

How much rain and snow does 54490 get?

About 34.2 inches of precipitation a year and 57 inches of snowfall (NOAA 1991–2020 normals, Medford station).

How hot do summers get in Westboro, WI?

The average high peaks at 79 °F in July, with about 3 days a year at 90 °F or more.

What kind of soil does 54490 have?

The USDA soil survey maps Magnor at the center of ZIP 54490: silt loam, somewhat poorly drained, pH about 5.0 (strongly acidic).

Did spring come early in Westboro, WI in 2026?

Spring leaf-out near 54490 came on Apr 16 in 2026, 6 days earlier than the 1991–2020 average (Apr 22), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Westboro, WI?

Long-day onions: the longest day near 54490 is 15 h 40 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 54490 change?

Yes. The 2012 USDA map put 54490 in zone 3b; the 2023 map puts it in zone 4a. The newer map uses 1991–2020 data and more weather stations.