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

Planting zone for 48117 — Carleton, MI

ZIP code 48117 (Carleton, Monroe County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 27 and the first fall frost October 20.

Where ZIP 48117 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.

Zone6b−5 to 0 °F
Coldest night−20.6 to −17.8 °C
Last frostApr 27
First frostOct 20
2012 zone6a

Was 6a 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 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Carleton, MI…

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 Carleton, MI

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 27median — 50% chance of a later frost
Safe for tender plantsMay 13only 10% chance of frost after
First fall frostOctober 20median — 10% chance by Oct 4
Growing season176 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 15 and returns around November 1.

From the NOAA station Carleton 2w, MI — 2 miles away, elevation 627 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 48117

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 16 – Mar 30
SpinachSow outdoors · Mar 16 – Apr 6
Broccoli, cabbageStart indoors · Feb 16 – Mar 2
Broccoli, cabbageTransplant · Apr 6 – Apr 20
Onion setsPlant outdoors · Mar 30 – Apr 13
PotatoesPlant outdoors · Apr 6 – Apr 20
LettuceSow outdoors · Mar 30 – Apr 13
Carrots, beetsSow outdoors · Apr 6 – Apr 20
TomatoesStart indoors · Mar 2 – Mar 16
TomatoesTransplant · May 4 – May 18
Peppers, eggplantStart indoors · Feb 16 – Mar 2
Peppers, eggplantTransplant · May 11 – May 25
BeansSow outdoors · May 4 – May 18
Sweet cornSow outdoors · May 4 – May 18
Cucumbers, squashSow outdoors · May 4 – May 18
Fall lettuce, spinachSow outdoors · Aug 25 – Sep 8
GarlicPlant cloves · Oct 6 – Nov 10
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 27) and first fall frost (Oct 20) 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 48117 came on Apr 1 — 7 days earlier than the 1991–2020 average (Apr 8).

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 6b in Michigan

582 plants native to the lower 48 states, recorded in Michigan, and rated by the USDA to survive −5 °F or colder — the bottom of zone 6b. Each links to its USDA PLANTS profile.

Trees 58

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 105

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 221

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine bistort1 ft · blooms mid spring · high shade tolerance · to −38 °Falpine sweetvetch2 ft · blooms early summer · high shade tolerance · to −62 °FAmerican bur-reed3 ft · blooms indeterminate · medium shade tolerance · to −33 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °FAmerican lotus3 ft · blooms mid summer · high shade tolerance · to −36 °F

Grasses 175

alpine timothy1.4 ft · blooms late spring · medium shade tolerance · to −43 °FAmerican beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °Farctic brome3 ft · blooms early summer · low shade tolerance · to −33 °Fautumn bluegrass1.5 ft · blooms late spring · medium shade tolerance · to −8 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °Fbeaked sedge4 ft · blooms late spring · low shade tolerance · to −38 °F

Vines 8

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °Ffrost grape83 ft · blooms late spring · medium shade tolerance · to −23 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Fsummer grape30 ft · blooms late spring · low shade tolerance · to −23 °Ftrumpet creeper2 ft · blooms summer · high shade tolerance · to −13 °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 Carleton, MI.

Soil in Carleton, MI

The soil mapped at the center of ZIP 48117 is Lenawee — silty clay loam, poorly drained.

TextureSilty clay loamholds water and nutrients; slow to drain and warm up
pH6.5neutral; most vegetables like 6.0–7.0
DrainagePoorly drainedconsider raised beds
Organic matter4.8%moderate
Hydrologic groupDwater soaks in very slowly
Farmland classPrime farmland if drainedUSDA classification

Map unit: Lenawee silty clay loam, 0 to 1 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 48117; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Carleton, MI

Summer high84 °Faverage high, July
Winter low17 °Faverage low, January
Hot days12days a year at 90 °F or more
Freezing nights130nights a year at 32 °F or less
Growing degree days2,889base 50 °F — the season’s usable heat
Longest day15 h 15 mindaylight on June 21
Shortest day9 h 06 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation35 inper year, rain and melted snow

Average high and low, by month

10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 33 °F, low 17 °F 33°17° JanFebruary: average high 36 °F, low 18 °F 36°18° FebMarch: average high 46 °F, low 27 °F 46°27° MarApril: average high 59 °F, low 37 °F 59°37° AprMay: average high 70 °F, low 48 °F 70°48° MayJune: average high 80 °F, low 58 °F 80°58° JunJuly: average high 84 °F, low 62 °F 84°62° JulAugust: average high 81 °F, low 60 °F 81°60° AugSeptember: average high 75 °F, low 53 °F 75°53° SepOctober: average high 62 °F, low 42 °F 62°42° OctNovember: average high 49 °F, low 32 °F 49°32° NovDecember: average high 38 °F, low 24 °F 38°24° Dec

Precipitation by month inches

0″1″2″3″4″January: 2.18 in precipitation 2.2 JanFebruary: 1.92 in precipitation 1.9 FebMarch: 2.53 in precipitation 2.5 MarApril: 3.19 in precipitation 3.2 AprMay: 3.91 in precipitation 3.9 MayJune: 3.42 in precipitation 3.4 JunJuly: 3.25 in precipitation 3.3 JulAugust: 3.43 in precipitation 3.4 AugSeptember: 3.38 in precipitation 3.4 SepOctober: 2.93 in precipitation 2.9 OctNovember: 2.53 in precipitation 2.5 NovDecember: 2.28 in precipitation 2.3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Carleton 2w, MI (2 mi away); precipitation: Carleton 2w, MI (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

481646b
New Boston, MI · 6 mi
481626b
Monroe, MI · 6 mi
481346b
Flat Rock, MI · 7 mi
481596a
Maybee, MI · 7 mi
481666b
Newport, MI · 7 mi
481796b
South Rockwood, MI · 8 mi
481916a
Willis, MI · 9 mi
481116a
Belleville, MI · 10 mi

Michigan planting zones →

Questions about 48117

What planting zone is ZIP code 48117?

ZIP code 48117 (Carleton, MI) is in USDA hardiness zone 6b on the 2023 map: the coldest night of an average winter reaches −5 to 0 °F (−20.6 to −17.8 °C).

When is the last frost in Carleton, MI?

The median last spring frost (32 °F) near 48117 is April 27; after May 13 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Carleton 2w station.

When is the first frost in Carleton, MI?

The median first fall frost near 48117 is October 20, giving a median frost-free growing season of 176 days.

When should I plant tomatoes in 48117?

Start tomato seeds indoors around Mar 2 – Mar 16 and set transplants outside around May 4 – May 18, one to three weeks after the median last frost.

How much rain and snow does 48117 get?

About 35 inches of precipitation a year (NOAA 1991–2020 normals, Carleton 2w station).

How hot do summers get in Carleton, MI?

The average high peaks at 84 °F in July, with about 12 days a year at 90 °F or more.

What kind of soil does 48117 have?

The USDA soil survey maps Lenawee at the center of ZIP 48117: silty clay loam, poorly drained, pH about 6.5 (neutral).

Did spring come early in Carleton, MI in 2026?

Spring leaf-out near 48117 came on Apr 1 in 2026, 7 days earlier than the 1991–2020 average (Apr 8), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Carleton, MI?

Long-day onions: the longest day near 48117 is 15 h 15 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 48117 change?

Yes. The 2012 USDA map put 48117 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.