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

Planting zone for 53188 — Waukesha, WI

ZIP code 53188 (Waukesha, Waukesha County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is May 1 and the first fall frost October 13.

Where ZIP 53188 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 frostMay 1

First frostOct 13

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 Waukesha, 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 Waukesha, 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 — 2 miles away, 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 53188

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 53188 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 Waukesha, WI.

Soil in Waukesha, WI

The soil mapped at the center of ZIP 53188 is Theresa — silt loam, well drained.

TextureSilt loama good balance for most vegetables

pH7.0neutral; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter2%moderate

Hydrologic groupCwater soaks in slowly

Farmland classprime farmlandUSDA classification

Map unit: Theresa silt loam, 2 to 6 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 53188; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Waukesha, WI

Summer high81 °Faverage high, July

Winter low12 °Faverage low, January

Hot days11days a year at 90 °F or more

Freezing nights143nights a year at 32 °F or less

Growing degree days2,535base 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 inper year, rain and melted snow

Snowfall37 inper year; 62 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: Waukesha Wwtp, WI (2 mi away); precipitation: Waukesha Wwtp, WI (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5b.

Genesee Depot, WI · 6 mi

530455b

Brookfield, WI · 8 mi

All 4 ZIP codes in Waukesha → · Wisconsin planting zones →

Questions about 53188

What planting zone is ZIP code 53188?

ZIP code 53188 (Waukesha, 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 Waukesha, WI?

The median last spring frost (32 °F) near 53188 is May 1; after May 18 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Waukesha Wwtp station.

When is the first frost in Waukesha, WI?

The median first fall frost near 53188 is October 13, giving a median frost-free growing season of 162 days.

When should I plant tomatoes in 53188?

Start tomato seeds indoors around Mar 6 – Mar 20 and set transplants outside around May 8 – May 22, one to three weeks after the median last frost.

How much rain and snow does 53188 get?

About 36 inches of precipitation a year and 37 inches of snowfall (NOAA 1991–2020 normals, Waukesha Wwtp station).

How hot do summers get in Waukesha, WI?

The average high peaks at 81 °F in July, with about 11 days a year at 90 °F or more.

What kind of soil does 53188 have?

The USDA soil survey maps Theresa at the center of ZIP 53188: silt loam, well drained, pH about 7.0 (neutral).

Did spring come early in Waukesha, WI in 2026?

Spring leaf-out near 53188 came on Mar 30 in 2026, 14 days earlier than the 1991–2020 average (Apr 13), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Waukesha, WI?

Long-day onions: the longest day near 53188 is 15 h 22 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).