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

Planting zone for 48161 — Monroe, MI

ZIP code 48161 (Monroe, Monroe County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 23 and the first fall frost October 23.

Where ZIP 48161 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 23
First frostOct 23
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 Monroe, 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 Monroe, MI

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 23median — 50% chance of a later frost
Safe for tender plantsMay 7only 10% chance of frost after
First fall frostOctober 23median — 10% chance by Oct 9
Growing season182 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 14 and returns around November 4.

From the NOAA station Monroe, MI — 3 miles away, elevation 587 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 48161

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 12 – Mar 26
SpinachSow outdoors · Mar 12 – Apr 2
Broccoli, cabbageStart indoors · Feb 12 – Feb 26
Broccoli, cabbageTransplant · Apr 2 – Apr 16
Onion setsPlant outdoors · Mar 26 – Apr 9
PotatoesPlant outdoors · Apr 2 – Apr 16
LettuceSow outdoors · Mar 26 – Apr 9
Carrots, beetsSow outdoors · Apr 2 – Apr 16
TomatoesStart indoors · Feb 26 – Mar 12
TomatoesTransplant · Apr 30 – May 14
Peppers, eggplantStart indoors · Feb 12 – Feb 26
Peppers, eggplantTransplant · May 7 – May 21
BeansSow outdoors · Apr 30 – May 14
Sweet cornSow outdoors · Apr 30 – May 14
Cucumbers, squashSow outdoors · Apr 30 – May 14
Fall lettuce, spinachSow outdoors · Aug 28 – Sep 11
GarlicPlant cloves · Oct 9 – Nov 13
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 23) and first fall frost (Oct 23) 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 48161 came on Mar 26 — 11 days earlier than the 1991–2020 average (Apr 6).

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 Monroe, MI.

Soil in Monroe, MI

The soil mapped at the center of ZIP 48161 is Selfridge — loamy sand, somewhat poorly drained.

TextureLoamy sanddrains and warms fast; dries out and needs more feeding
pH6.3slightly acidic; most vegetables like 6.0–7.0
DrainageSomewhat poorly drainedconsider raised beds
Organic matter2.6%moderate
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classprime farmlandUSDA classification

Map unit: Selfridge loamy sand, 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 48161; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Monroe, MI

Summer high85 °Faverage high, July
Winter low18 °Faverage low, January
Hot days14days a year at 90 °F or more
Freezing nights128nights a year at 32 °F or less
Growing degree days2,979base 50 °F — the season’s usable heat
Longest day15 h 14 mindaylight on June 21
Shortest day9 h 07 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation35.2 inper year, rain and melted snow

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 33 °F, low 18 °F 33°18° JanFebruary: average high 35 °F, low 19 °F 35°19° FebMarch: average high 45 °F, low 27 °F 45°27° MarApril: average high 58 °F, low 38 °F 58°38° AprMay: average high 69 °F, low 49 °F 69°49° MayJune: average high 80 °F, low 59 °F 80°59° JunJuly: average high 85 °F, low 63 °F 85°63° JulAugust: average high 82 °F, low 61 °F 82°61° AugSeptember: average high 75 °F, low 54 °F 75°54° SepOctober: average high 63 °F, low 42 °F 63°42° OctNovember: average high 49 °F, low 33 °F 49°33° NovDecember: average high 38 °F, low 24 °F 38°24° Dec

Precipitation by month inches

0″1″2″3″4″January: 2.30 in precipitation 2.3 JanFebruary: 2.02 in precipitation 2.0 FebMarch: 2.80 in precipitation 2.8 MarApril: 3.32 in precipitation 3.3 AprMay: 3.88 in precipitation 3.9 MayJune: 3.65 in precipitation 3.6 JunJuly: 3.35 in precipitation 3.4 JulAugust: 3.55 in precipitation 3.5 AugSeptember: 2.86 in precipitation 2.9 SepOctober: 2.61 in precipitation 2.6 OctNovember: 2.71 in precipitation 2.7 NovDecember: 2.15 in precipitation 2.1 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Monroe, MI (3 mi away); precipitation: Monroe 3.0 S, MI (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

481626b
Monroe, MI · 4 mi
481456b
La Salle, MI · 4 mi
481406a
Ida, MI · 6 mi
481576b
Luna Pier, MI · 7 mi
481336b
Erie, MI · 9 mi
481596a
Maybee, MI · 9 mi
481776b
Samaria, MI · 9 mi
481826b
Temperance, MI · 10 mi

All 2 ZIP codes in Monroe → · Michigan planting zones →

Questions about 48161

What planting zone is ZIP code 48161?

ZIP code 48161 (Monroe, 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 Monroe, MI?

The median last spring frost (32 °F) near 48161 is April 23; after May 7 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Monroe station.

When is the first frost in Monroe, MI?

The median first fall frost near 48161 is October 23, giving a median frost-free growing season of 182 days.

When should I plant tomatoes in 48161?

Start tomato seeds indoors around Feb 26 – Mar 12 and set transplants outside around Apr 30 – May 14, one to three weeks after the median last frost.

How much rain and snow does 48161 get?

About 35.2 inches of precipitation a year (NOAA 1991–2020 normals, Monroe 3.0 S station).

How hot do summers get in Monroe, MI?

The average high peaks at 85 °F in July, with about 14 days a year at 90 °F or more.

What kind of soil does 48161 have?

The USDA soil survey maps Selfridge at the center of ZIP 48161: loamy sand, somewhat poorly drained, pH about 6.3 (slightly acidic).

Did spring come early in Monroe, MI in 2026?

Spring leaf-out near 48161 came on Mar 26 in 2026, 11 days earlier than the 1991–2020 average (Apr 6), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Monroe, MI?

Long-day onions: the longest day near 48161 is 15 h 14 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 48161 change?

Yes. The 2012 USDA map put 48161 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.