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

Planting zone for New Berlin, WI

New Berlin, WI is in USDA zone 5b across its 2 ZIP codes. The median last spring frost is May 1 and the first fall frost October 13.

New Berlin on the zone map

Outlined: its 2 ZIP code areas · 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

ZIP codes2

Last frostMay 1

First frostOct 13

Growing season162 days

5b 2 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for New Berlin, 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 New Berlin, WI

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 1median — 50% chance of a later frost

Safe for tender plantsMay 18only 10% chance of frost after

First fall frostOctober 13median — 10% chance by Sep 29

Growing season162 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 19 and returns around October 23.

From the NOAA station Waukesha Wwtp, WI, elevation 791 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 New Berlin

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 20 – Apr 3

SpinachSow outdoors · Mar 20 – Apr 10

Broccoli, cabbageStart indoors · Feb 20 – Mar 6

Broccoli, cabbageTransplant · Apr 10 – Apr 24

Onion setsPlant outdoors · Apr 3 – Apr 17

PotatoesPlant outdoors · Apr 10 – Apr 24

LettuceSow outdoors · Apr 3 – Apr 17

Carrots, beetsSow outdoors · Apr 10 – Apr 24

TomatoesStart indoors · Mar 6 – Mar 20

TomatoesTransplant · May 8 – May 22

Peppers, eggplantStart indoors · Feb 20 – Mar 6

Peppers, eggplantTransplant · May 15 – May 29

BeansSow outdoors · May 8 – May 22

Sweet cornSow outdoors · May 8 – May 22

Cucumbers, squashSow outdoors · May 8 – May 22

Fall lettuce, spinachSow outdoors · Aug 18 – Sep 1

GarlicPlant cloves · Sep 29 – Nov 3

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 1) and first fall frost (Oct 13) 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 53151 came on Mar 30 — 14 days earlier than the 1991–2020 average (Apr 13).

average
Apr 132026
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 New Berlin, WI.

Soil in New Berlin, WI

The soil mapped at the center of ZIP 53151 is Houghton — muck, very poorly drained.

TextureMucktop layer

DrainageVery poorly drainedconsider raised beds

Organic matter45%high

Hydrologic groupA/Ddrains fast once dried out; wet otherwise

Farmland classFarmland of statewide importanceUSDA classification

Map unit: Houghton muck, 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 53151; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in New Berlin, WI

Summer high83 °Faverage high, July

Winter low12 °Faverage low, January

Hot days12days a year at 90 °F or more

Freezing nights159nights a year at 32 °F or less

Growing degree days2,635base 50 °F — the season’s usable heat

Longest day15 h 22 mindaylight on June 21

Shortest day9 h 00 mindaylight on December 21

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

Precipitation36.5 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: Hales Corners/Whitnall Park/Bo, WI (4 mi away); precipitation: West Allis 0.7 Sse, WI (4 mi away). Daylight is calculated from latitude.

ZIP codes in New Berlin

Wisconsin planting zones →

Questions about New Berlin

What planting zone is New Berlin, WI?

New Berlin, WI is in USDA hardiness zone 5b on the 2023 map (5b: −15 to −10 °F).

When is the last frost in New Berlin, WI?

The median last spring frost is May 1 and the median first fall frost is October 13 (NOAA 1991–2020 normals, Waukesha Wwtp station).

When can I plant a garden in New Berlin, WI?

Cool-season crops like peas and spinach go in around Mar 20 – Apr 10; tomatoes, peppers, beans and squash after about May 8, once frost risk has passed.

What kind of onions grow in New Berlin, WI?

Long-day onions: the longest day is 15 h 22 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

How much rain and snow does New Berlin, WI get?

About 36.5 inches of precipitation a year (NOAA 1991–2020 normals).