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

Planting zone for 53121 — Elkhorn, WI

ZIP code 53121 (Elkhorn, Walworth County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is April 28 and the first fall frost October 14.

Where ZIP 53121 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 28

First frostOct 14

2012 zone5b

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 5b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Elkhorn, 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 Elkhorn, WI

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 28median — 50% chance of a later frost

Safe for tender plantsMay 14only 10% chance of frost after

First fall frostOctober 14median — 10% chance by Sep 28

Growing season168 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 15 and returns around October 25.

From the NOAA station Delavan Wwtp, WI — 9 miles away, elevation 883 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 53121

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 17 – Mar 31

SpinachSow outdoors · Mar 17 – Apr 7

Broccoli, cabbageStart indoors · Feb 17 – Mar 3

Broccoli, cabbageTransplant · Apr 7 – Apr 21

Onion setsPlant outdoors · Mar 31 – Apr 14

PotatoesPlant outdoors · Apr 7 – Apr 21

LettuceSow outdoors · Mar 31 – Apr 14

Carrots, beetsSow outdoors · Apr 7 – Apr 21

TomatoesStart indoors · Mar 3 – Mar 17

TomatoesTransplant · May 5 – May 19

Peppers, eggplantStart indoors · Feb 17 – Mar 3

Peppers, eggplantTransplant · May 12 – May 26

BeansSow outdoors · May 5 – May 19

Sweet cornSow outdoors · May 5 – May 19

Cucumbers, squashSow outdoors · May 5 – May 19

Fall lettuce, spinachSow outdoors · Aug 19 – Sep 2

GarlicPlant cloves · Sep 30 – Nov 4

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 28) and first fall frost (Oct 14) 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 53121 came on Mar 30 — 12 days earlier than the 1991–2020 average (Apr 11).

average
Apr 112026
Mar 30

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 5b in Wisconsin

518 plants native to the lower 48 states, recorded in Wisconsin, and rated by the USDA to survive −15 °F or colder — the bottom of zone 5b. 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 Elkhorn, WI.

Soil in Elkhorn, WI

The soil mapped at the center of ZIP 53121 is Fox — 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%moderate

Hydrologic groupBwater soaks in moderately

Farmland classprime farmlandUSDA classification

Map unit: Fox silt loam, 0 to 2 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 53121; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Elkhorn, WI

Summer high83 °Faverage high, July

Winter low13 °Faverage low, January

Hot days13days a year at 90 °F or more

Freezing nights143nights a year at 32 °F or less

Growing degree days2,696base 50 °F — the season’s usable heat

Longest day15 h 20 mindaylight on June 21

Shortest day9 h 02 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

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Delavan Wwtp, WI (9 mi away); precipitation: Delavan Wwtp, WI (9 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5b.

531765b

Springfield, WI · 8 mi

Williams Bay, WI · 10 mi

531485b

Lyons, WI · 10 mi

531385b

Honey Creek, WI · 12 mi

531905b

Whitewater, WI · 12 mi

531475b

Lake Geneva, WI · 12 mi

Wisconsin planting zones →

Questions about 53121

What planting zone is ZIP code 53121?

ZIP code 53121 (Elkhorn, 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 Elkhorn, WI?

The median last spring frost (32 °F) near 53121 is April 28; after May 14 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Delavan Wwtp station.

When is the first frost in Elkhorn, WI?

The median first fall frost near 53121 is October 14, giving a median frost-free growing season of 168 days.

When should I plant tomatoes in 53121?

Start tomato seeds indoors around Mar 3 – Mar 17 and set transplants outside around May 5 – May 19, one to three weeks after the median last frost.

How much rain and snow does 53121 get?

About 36.7 inches of precipitation a year (NOAA 1991–2020 normals, Delavan Wwtp station).

How hot do summers get in Elkhorn, WI?

The average high peaks at 83 °F in July, with about 13 days a year at 90 °F or more.

What kind of soil does 53121 have?

The USDA soil survey maps Fox at the center of ZIP 53121: silt loam, well drained, pH about 6.2 (slightly acidic).

Did spring come early in Elkhorn, WI in 2026?

Spring leaf-out near 53121 came on Mar 30 in 2026, 12 days earlier than the 1991–2020 average (Apr 11), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Elkhorn, WI?

Long-day onions: the longest day near 53121 is 15 h 20 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).