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

Planting zone for 53549 — Jefferson, WI

ZIP code 53549 (Jefferson, Jefferson County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is April 25 and the first fall frost October 18.

Where ZIP 53549 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 25

First frostOct 18

2012 zone5a

Was 5a on the 2012 map — half a zone warmer now. 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 Jefferson, 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 Jefferson, WI

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 25median — 50% chance of a later frost

Safe for tender plantsMay 9only 10% chance of frost after

First fall frostOctober 18median — 10% chance by Oct 2

Growing season173 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 15 and returns around October 29.

From the NOAA station Jefferson Wwtp, WI — 2 miles away, elevation 784 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 53549

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 14 – Mar 28

SpinachSow outdoors · Mar 14 – Apr 4

Broccoli, cabbageStart indoors · Feb 14 – Feb 28

Broccoli, cabbageTransplant · Apr 4 – Apr 18

Onion setsPlant outdoors · Mar 28 – Apr 11

PotatoesPlant outdoors · Apr 4 – Apr 18

LettuceSow outdoors · Mar 28 – Apr 11

Carrots, beetsSow outdoors · Apr 4 – Apr 18

TomatoesStart indoors · Feb 28 – Mar 14

TomatoesTransplant · May 2 – May 16

Peppers, eggplantStart indoors · Feb 14 – Feb 28

Peppers, eggplantTransplant · May 9 – May 23

BeansSow outdoors · May 2 – May 16

Sweet cornSow outdoors · May 2 – May 16

Cucumbers, squashSow outdoors · May 2 – May 16

Fall lettuce, spinachSow outdoors · Aug 23 – Sep 6

GarlicPlant cloves · Oct 4 – Nov 8

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 25) and first fall frost (Oct 18) 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 53549 came on Mar 30 — 13 days earlier than the 1991–2020 average (Apr 12).

average
Apr 122026
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 Jefferson, WI.

Soil in Jefferson, WI

The soil mapped at the center of ZIP 53549 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 53549; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Jefferson, WI

Summer high82 °Faverage high, July

Winter low11 °Faverage low, January

Hot days12days a year at 90 °F or more

Freezing nights143nights a year at 32 °F or less

Growing degree days2,769base 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)

Precipitation38.7 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: Jefferson Wwtp, WI (2 mi away); precipitation: Jefferson Wwtp, WI (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5b.

531375b

Helenville, WI · 5 mi

530385b

Johnson Creek, WI · 7 mi

535385b

Fort Atkinson, WI · 7 mi

531785b

Sullivan, WI · 9 mi

535515b

Lake Mills, WI · 10 mi

531565b

Palmyra, WI · 11 mi

530945b

Watertown, WI · 11 mi

531905b

Whitewater, WI · 12 mi

Wisconsin planting zones →

Questions about 53549

What planting zone is ZIP code 53549?

ZIP code 53549 (Jefferson, 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 Jefferson, WI?

The median last spring frost (32 °F) near 53549 is April 25; after May 9 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Jefferson Wwtp station.

When is the first frost in Jefferson, WI?

The median first fall frost near 53549 is October 18, giving a median frost-free growing season of 173 days.

When should I plant tomatoes in 53549?

Start tomato seeds indoors around Feb 28 – Mar 14 and set transplants outside around May 2 – May 16, one to three weeks after the median last frost.

How much rain and snow does 53549 get?

About 38.7 inches of precipitation a year (NOAA 1991–2020 normals, Jefferson Wwtp station).

How hot do summers get in Jefferson, WI?

The average high peaks at 82 °F in July, with about 12 days a year at 90 °F or more.

What kind of soil does 53549 have?

The USDA soil survey maps Houghton at the center of ZIP 53549: muck, very poorly drained.

Did spring come early in Jefferson, WI in 2026?

Spring leaf-out near 53549 came on Mar 30 in 2026, 13 days earlier than the 1991–2020 average (Apr 12), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Jefferson, WI?

Long-day onions: the longest day near 53549 is 15 h 22 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 53549 change?

Yes. The 2012 USDA map put 53549 in zone 5a; the 2023 map puts it in zone 5b. The newer map uses 1991–2020 data and more weather stations.