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

Planting zone for Dearborn, MI

Dearborn, MI is in USDA zone 6b across its 6 ZIP codes. The median last spring frost is May 1 and the first fall frost October 15.

Dearborn on the zone map

Outlined: its 4 ZIP code areas · 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
ZIP codes6
Last frostMay 1
First frostOct 15
Growing season166 days

6b 6 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

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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 Dearborn, MI

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 1median — 50% chance of a later frost
Safe for tender plantsMay 18only 10% chance of frost after
First fall frostOctober 15median — 10% chance by Oct 1
Growing season166 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 20 and returns around October 28.

From the NOAA station Dearborn, MI, elevation 604 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 Dearborn

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 20 – Apr 3
SpinachSow outdoors · Mar 20 – Apr 10
Broccoli, cabbageStart indoors · Feb 20 – Mar 6
Broccoli, cabbageTransplant · Apr 10 – Apr 24
Onion setsPlant outdoors · Apr 3 – Apr 17
PotatoesPlant outdoors · Apr 10 – Apr 24
LettuceSow outdoors · Apr 3 – Apr 17
Carrots, beetsSow outdoors · Apr 10 – Apr 24
TomatoesStart indoors · Mar 6 – Mar 20
TomatoesTransplant · May 8 – May 22
Peppers, eggplantStart indoors · Feb 20 – Mar 6
Peppers, eggplantTransplant · May 15 – May 29
BeansSow outdoors · May 8 – May 22
Sweet cornSow outdoors · May 8 – May 22
Cucumbers, squashSow outdoors · May 8 – May 22
Fall lettuce, spinachSow outdoors · Aug 20 – Sep 3
GarlicPlant cloves · Oct 1 – Nov 5
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 1) and first fall frost (Oct 15) 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 48120 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

Shrubs 105

Wildflowers & perennials 221

Grasses 175

Vines 8

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 Dearborn, MI.

Soil in Dearborn, MI

The soil mapped at the center of ZIP 48120 is Riverfront — sandy loam, well drained. Much of the area is built over (urban land); this is the natural soil underneath.

TextureSandy loamdrains and warms fast; dries out and needs more feeding
pH8.0alkaline; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter6.67%high
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Urban land-Riverfront complex, 0 to 4 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 48120; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Dearborn, MI

Summer high84 °Faverage high, July
Winter low19 °Faverage low, January
Hot days17days a year at 90 °F or more
Freezing nights125nights a year at 32 °F or less
Growing degree days3,018base 50 °F — the season’s usable heat
Longest day15 h 17 mindaylight on June 21
Shortest day9 h 05 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation34.9 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 19 °F 33°19° JanFebruary: average high 36 °F, low 20 °F 36°20° 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 79 °F, low 59 °F 79°59° JunJuly: average high 84 °F, low 63 °F 84°63° JulAugust: average high 82 °F, low 62 °F 82°62° AugSeptember: average high 75 °F, low 55 °F 75°55° SepOctober: average high 63 °F, low 43 °F 63°43° OctNovember: average high 49 °F, low 33 °F 49°33° NovDecember: average high 37 °F, low 25 °F 37°25° Dec

Precipitation by month inches

0″1″2″3″4″January: 2.07 in precipitation 2.1 JanFebruary: 2.06 in precipitation 2.1 FebMarch: 2.50 in precipitation 2.5 MarApril: 3.23 in precipitation 3.2 AprMay: 3.69 in precipitation 3.7 MayJune: 3.67 in precipitation 3.7 JunJuly: 3.39 in precipitation 3.4 JulAugust: 3.51 in precipitation 3.5 AugSeptember: 3.04 in precipitation 3.0 SepOctober: 2.76 in precipitation 2.8 OctNovember: 2.62 in precipitation 2.6 NovDecember: 2.35 in precipitation 2.4 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Dearborn #2, MI (3 mi away); precipitation: Dearborn #2, MI (3 mi away). Daylight is calculated from latitude.

ZIP codes in Dearborn

Michigan planting zones →

Questions about Dearborn

What planting zone is Dearborn, MI?

Dearborn, MI is in USDA hardiness zone 6b on the 2023 map (6b: −5 to 0 °F).

When is the last frost in Dearborn, MI?

The median last spring frost is May 1 and the median first fall frost is October 15 (NOAA 1991–2020 normals, Dearborn station).

When can I plant a garden in Dearborn, MI?

Cool-season crops like peas and spinach go in around Mar 20 – Apr 10; tomatoes, peppers, beans and squash after about May 8, once frost risk has passed.

What kind of onions grow in Dearborn, MI?

Long-day onions: the longest day is 15 h 17 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

How much rain and snow does Dearborn, MI get?

About 34.9 inches of precipitation a year (NOAA 1991–2020 normals).