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

Planting zone for 53517 — Blue Mounds, WI

ZIP code 53517 (Blue Mounds, Dane County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 7 and the first fall frost October 1.

Where ZIP 53517 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.

Zone5a−20 to −15 °F
Coldest night−28.9 to −26.1 °C
Last frostMay 7
First frostOct 1
2012 zone5b

Was 5b on the 2012 map — half a zone colder now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 5a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Blue Mounds, 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 Blue Mounds, WI

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 7median — 50% chance of a later frost
Safe for tender plantsMay 22only 10% chance of frost after
First fall frostOctober 1median — 10% chance by Sep 18
Growing season148 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 27 and returns around October 12.

From the NOAA station Mazomanie Wwtp, WI — 8 miles away, elevation 764 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 53517

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 26 – Apr 9
SpinachSow outdoors · Mar 26 – Apr 16
Broccoli, cabbageStart indoors · Feb 26 – Mar 12
Broccoli, cabbageTransplant · Apr 16 – Apr 30
Onion setsPlant outdoors · Apr 9 – Apr 23
PotatoesPlant outdoors · Apr 16 – Apr 30
LettuceSow outdoors · Apr 9 – Apr 23
Carrots, beetsSow outdoors · Apr 16 – Apr 30
TomatoesStart indoors · Mar 12 – Mar 26
TomatoesTransplant · May 14 – May 28
Peppers, eggplantStart indoors · Feb 26 – Mar 12
Peppers, eggplantTransplant · May 21 – Jun 4
BeansSow outdoors · May 14 – May 28
Sweet cornSow outdoors · May 14 – May 28
Cucumbers, squashSow outdoors · May 14 – May 28
Fall lettuce, spinachSow outdoors · Aug 6 – Aug 20
GarlicPlant cloves · Sep 17 – Oct 22
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 7) and first fall frost (Oct 1) 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 53517 came on Mar 30 — 14 days earlier than the 1991–2020 average (Apr 13).

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.

Trees 48

American basswood100 ft · blooms late spring · low shade tolerance · to −46 °FAmerican beech80 ft · blooms mid spring · low shade tolerance · to −44 °FAmerican chestnut115 ft · blooms early summer · high shade tolerance · to −33 °FAmerican elm120 ft · blooms early spring · medium shade tolerance · to −46 °FAmerican sycamore100 ft · blooms spring · medium shade tolerance · to −34 °Farborvitae50 ft · blooms mid spring · medium shade tolerance · to −33 °F

Shrubs 93

alderleaf buckthorn3 ft · blooms late spring · low shade tolerance · to −33 °FAllegheny serviceberry35 ft · blooms early spring · low shade tolerance · to −38 °Falternateleaf dogwood25 ft · blooms mid spring · low shade tolerance · to −47 °FAmerican black currant3 ft · blooms early spring · to −46 °FAmerican hazelnut10 ft · blooms spring · medium shade tolerance · to −33 °FAmerican hornbeam30 ft · blooms mid spring · low shade tolerance · to −34 °F

Wildflowers & perennials 191

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °FAmerican bur-reed3 ft · blooms indeterminate · medium shade tolerance · to −33 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °FAmerican licorice4 ft · blooms late spring · medium shade tolerance · to −38 °FAmerican lotus3 ft · blooms mid summer · high shade tolerance · to −36 °FAmerican pokeweed7 ft · blooms mid summer · low shade tolerance · to −33 °F

Grasses 158

American beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °Farctic brome3 ft · blooms early summer · low shade tolerance · to −33 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °Fbeaked sedge4 ft · blooms late spring · low shade tolerance · to −38 °Fbeaked spikerush3 ft · blooms late spring · high shade tolerance · to −28 °FBebb's sedge3 ft · blooms late spring · low shade tolerance · to −38 °F

Vines 5

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Fsummer grape30 ft · blooms late spring · low shade tolerance · to −23 °FVirginia creeper1 ft · blooms late spring · medium shade tolerance · to −28 °F

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 Blue Mounds, WI.

Soil in Blue Mounds, WI

The soil mapped at the center of ZIP 53517 is Basco — silt loam, well drained.

TextureSilt loama good balance for most vegetables
pH5.9moderately acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter3%moderate
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Basco silt loam, 12 to 20 percent slopes, eroded.

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 53517; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Blue Mounds, WI

Summer high82 °Faverage high, July
Winter low7 °Faverage low, January
Hot days11days a year at 90 °F or more
Freezing nights156nights a year at 32 °F or less
Growing degree days2,486base 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)
Precipitation40.6 inper year, rain and melted snow

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 28 °F, low 7 °F 28°7° JanFebruary: average high 33 °F, low 10 °F 33°10° FebMarch: average high 44 °F, low 22 °F 44°22° MarApril: average high 58 °F, low 33 °F 58°33° AprMay: average high 70 °F, low 45 °F 70°45° MayJune: average high 79 °F, low 55 °F 79°55° JunJuly: average high 82 °F, low 58 °F 82°58° JulAugust: average high 81 °F, low 57 °F 81°57° AugSeptember: average high 74 °F, low 47 °F 74°47° SepOctober: average high 61 °F, low 37 °F 61°37° OctNovember: average high 46 °F, low 26 °F 46°26° NovDecember: average high 34 °F, low 14 °F 34°14° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 1.58 in precipitation 1.6 JanFebruary: 1.79 in precipitation 1.8 FebMarch: 2.28 in precipitation 2.3 MarApril: 3.89 in precipitation 3.9 AprMay: 4.51 in precipitation 4.5 MayJune: 5.53 in precipitation 5.5 JunJuly: 4.95 in precipitation 5.0 JulAugust: 4.73 in precipitation 4.7 AugSeptember: 3.78 in precipitation 3.8 SepOctober: 3.18 in precipitation 3.2 OctNovember: 2.37 in precipitation 2.4 NovDecember: 1.98 in precipitation 2.0 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Mazomanie Wwtp, WI (8 mi away); precipitation: Mt Horeb, WI (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5a.

535155a
Black Earth, WI · 6 mi
535075a
Barneveld, WI · 7 mi
535725a
Mount Horeb, WI · 8 mi
535825a
Ridgeway, WI · 8 mi
535035a
Arena, WI · 9 mi
535605a
Mazomanie, WI · 10 mi
535285a
Cross Plains, WI · 11 mi
535445a
Hollandale, WI · 13 mi

Wisconsin planting zones →

Questions about 53517

What planting zone is ZIP code 53517?

ZIP code 53517 (Blue Mounds, WI) is in USDA hardiness zone 5a on the 2023 map: the coldest night of an average winter reaches −20 to −15 °F (−28.9 to −26.1 °C).

When is the last frost in Blue Mounds, WI?

The median last spring frost (32 °F) near 53517 is May 7; after May 22 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Mazomanie Wwtp station.

When is the first frost in Blue Mounds, WI?

The median first fall frost near 53517 is October 1, giving a median frost-free growing season of 148 days.

When should I plant tomatoes in 53517?

Start tomato seeds indoors around Mar 12 – Mar 26 and set transplants outside around May 14 – May 28, one to three weeks after the median last frost.

How much rain and snow does 53517 get?

About 40.6 inches of precipitation a year (NOAA 1991–2020 normals, Mt Horeb station).

How hot do summers get in Blue Mounds, WI?

The average high peaks at 82 °F in July, with about 11 days a year at 90 °F or more.

What kind of soil does 53517 have?

The USDA soil survey maps Basco at the center of ZIP 53517: silt loam, well drained, pH about 5.9 (moderately acidic).

Did spring come early in Blue Mounds, WI in 2026?

Spring leaf-out near 53517 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 Blue Mounds, WI?

Long-day onions: the longest day near 53517 is 15 h 22 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 53517 change?

Yes. The 2012 USDA map put 53517 in zone 5b; the 2023 map puts it in zone 5a. The newer map uses 1991–2020 data and more weather stations.