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

Planting zone for Randolph, WI

Randolph, WI is in USDA zone 5a across its 2 ZIP codes. The median last spring frost is May 1 and the first fall frost October 11.

Randolph on the zone map

Outlined: its 1 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.

Zone5a−20 to −15 °F

ZIP codes2

Last frostMay 1

First frostOct 11

Growing season163 days

5a 2 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

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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 Randolph, 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 16only 10% chance of frost after

First fall frostOctober 11median — 10% chance by Sep 27

Growing season163 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 19 and returns around October 22.

From the NOAA station Town Of Westford, WI, elevation 879 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 Randolph

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 16 – Aug 30

GarlicPlant cloves · Sep 27 – Nov 1

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 1) and first fall frost (Oct 11) 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 53956 came on Apr 5 — 10 days earlier than the 1991–2020 average (Apr 15).

average
Apr 152026
Apr 5

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 5a in Wisconsin

510 plants native to the lower 48 states, recorded in Wisconsin, and rated by the USDA to survive −20 °F or colder — the bottom of zone 5a. 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 Randolph, WI.

Soil in Randolph, WI

The soil mapped at the center of ZIP 53956 is Ossian — silt loam, poorly drained.

TextureSilt loama good balance for most vegetables

pH7.0neutral; most vegetables like 6.0–7.0

DrainagePoorly drainedconsider raised beds

Organic matter6%high

Hydrologic groupB/Dmoderate when drained; wet otherwise

Farmland classPrime farmland if drainedUSDA classification

Map unit: Ossian silt 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 53956; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Randolph, WI

Summer high81 °Faverage high, July

Winter low8 °Faverage low, January

Hot days5days a year at 90 °F or more

Freezing nights157nights a year at 32 °F or less

Growing degree days2,497base 50 °F — the season’s usable heat

Longest day15 h 26 mindaylight on June 21

Shortest day8 h 56 mindaylight on December 21

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

Precipitation37.8 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: Town Of Westford, WI (8 mi away); precipitation: Town Of Westford, WI (8 mi away). Daylight is calculated from latitude.

ZIP codes in Randolph

Wisconsin planting zones →

Questions about Randolph

What planting zone is Randolph, WI?

Randolph, WI is in USDA hardiness zone 5a on the 2023 map (5a: −20 to −15 °F).

When is the last frost in Randolph, WI?

The median last spring frost is May 1 and the median first fall frost is October 11 (NOAA 1991–2020 normals, Town Of Westford station).

When can I plant a garden in Randolph, 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 Randolph, WI?

Long-day onions: the longest day is 15 h 26 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

How much rain and snow does Randolph, WI get?

About 37.8 inches of precipitation a year (NOAA 1991–2020 normals).