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

Planting zone for 54517 — Clam Lake, WI

ZIP code 54517 (Clam Lake, Ashland County) is in USDA zone 4a: the coldest winter night averages −30 to −25 °F. The median last spring frost is May 16 and the first fall frost September 30.

Where ZIP 54517 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 16

First frostSep 30

2012 zone4a

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 4a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Clam Lake, 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 Clam Lake, WI

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 16median — 50% chance of a later frost

Safe for tender plantsMay 27only 10% chance of frost after

First fall frostSeptember 30median — 10% chance by Sep 17

Growing season136 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 3 and returns around October 10.

From the NOAA station Clam Lake 4w, WI — 4 miles away, elevation 1,499 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 54517

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 4 – Apr 18

SpinachSow outdoors · Apr 4 – Apr 25

Broccoli, cabbageStart indoors · Mar 7 – Mar 21

Broccoli, cabbageTransplant · Apr 25 – May 9

Onion setsPlant outdoors · Apr 18 – May 2

PotatoesPlant outdoors · Apr 25 – May 9

LettuceSow outdoors · Apr 18 – May 2

Carrots, beetsSow outdoors · Apr 25 – May 9

TomatoesStart indoors · Mar 21 – Apr 4

TomatoesTransplant · May 23 – Jun 6

Peppers, eggplantStart indoors · Mar 7 – Mar 21

Peppers, eggplantTransplant · May 30 – Jun 13

BeansSow outdoors · May 23 – Jun 6

Sweet cornSow outdoors · May 23 – Jun 6

Cucumbers, squashSow outdoors · May 23 – Jun 6

Fall lettuce, spinachSow outdoors · Aug 5 – Aug 19

GarlicPlant cloves · Sep 16 – Oct 21

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 16) and first fall frost (Sep 30) 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 54517 came on Apr 22 — 3 days earlier than the 1991–2020 average (Apr 25).

average
Apr 252026
Apr 22

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).

Soil in Clam Lake, WI

The soil mapped at the center of ZIP 54517 is Keweenaw — sandy loam, well drained.

TextureSandy loamdrains and warms fast; dries out and needs more feeding

pH5.5moderately acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter1.5%low — add compost

Hydrologic groupAwater soaks in fast

Farmland classNot prime farmlandUSDA classification

Map unit: Keweenaw-Pence complex, 6 to 15 percent slopes, 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 54517; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Clam Lake, WI

Summer high76 °Faverage high, July

Winter low1 °Faverage low, January

Hot days1days a year at 90 °F or more

Freezing nights190nights a year at 32 °F or less

Growing degree days1,724base 50 °F — the season’s usable heat

Longest day15 h 46 mindaylight on June 21

Shortest day8 h 37 mindaylight on December 21

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

Precipitation33.9 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: Clam Lake 4w, WI (4 mi away); precipitation: Clam Lake 4w, WI (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

Grand View, WI · 19 mi

548464b

High Bridge, WI · 20 mi

Wisconsin planting zones →

Questions about 54517

What planting zone is ZIP code 54517?

ZIP code 54517 (Clam Lake, 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 Clam Lake, WI?

The median last spring frost (32 °F) near 54517 is May 16; after May 27 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Clam Lake 4w station.

When is the first frost in Clam Lake, WI?

The median first fall frost near 54517 is September 30, giving a median frost-free growing season of 136 days.

When should I plant tomatoes in 54517?

Start tomato seeds indoors around Mar 21 – Apr 4 and set transplants outside around May 23 – Jun 6, one to three weeks after the median last frost.

How much rain and snow does 54517 get?

About 33.9 inches of precipitation a year (NOAA 1991–2020 normals, Clam Lake 4w station).

How hot do summers get in Clam Lake, WI?

The average high peaks at 76 °F in July, with about 1 days a year at 90 °F or more.

What kind of soil does 54517 have?

The USDA soil survey maps Keweenaw at the center of ZIP 54517: sandy loam, well drained, pH about 5.5 (moderately acidic).

Did spring come early in Clam Lake, WI in 2026?

Spring leaf-out near 54517 came on Apr 22 in 2026, 3 days earlier than the 1991–2020 average (Apr 25), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Clam Lake, WI?

Long-day onions: the longest day near 54517 is 15 h 46 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).