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

Planting zone for 48418 — Byron, MI

ZIP code 48418 (Byron, Shiawassee County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is May 3 and the first fall frost October 12.

Where ZIP 48418 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.

Zone6a−10 to −5 °F
Coldest night−23.3 to −20.6 °C
Last frostMay 3
First frostOct 12
2012 zone6a

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Byron, 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 Byron, MI

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 3median — 50% chance of a later frost
Safe for tender plantsMay 20only 10% chance of frost after
First fall frostOctober 12median — 10% chance by Sep 30
Growing season161 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 23 and returns around October 27.

From the NOAA station Linden Wwtp, MI — 9 miles away, elevation 863 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 48418

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 22 – Apr 5
SpinachSow outdoors · Mar 22 – Apr 12
Broccoli, cabbageStart indoors · Feb 22 – Mar 8
Broccoli, cabbageTransplant · Apr 12 – Apr 26
Onion setsPlant outdoors · Apr 5 – Apr 19
PotatoesPlant outdoors · Apr 12 – Apr 26
LettuceSow outdoors · Apr 5 – Apr 19
Carrots, beetsSow outdoors · Apr 12 – Apr 26
TomatoesStart indoors · Mar 8 – Mar 22
TomatoesTransplant · May 10 – May 24
Peppers, eggplantStart indoors · Feb 22 – Mar 8
Peppers, eggplantTransplant · May 17 – May 31
BeansSow outdoors · May 10 – May 24
Sweet cornSow outdoors · May 10 – May 24
Cucumbers, squashSow outdoors · May 10 – May 24
Fall lettuce, spinachSow outdoors · Aug 17 – Aug 31
GarlicPlant cloves · Sep 28 – Nov 2
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 3) and first fall frost (Oct 12) 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 48418 came on Apr 2 — 9 days earlier than the 1991–2020 average (Apr 11).

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 6a in Michigan

580 plants native to the lower 48 states, recorded in Michigan, and rated by the USDA to survive −10 °F or colder — the bottom of zone 6a. 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 220

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 174

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 °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 °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 Byron, MI.

Soil in Byron, MI

The soil mapped at the center of ZIP 48418 is Conover — loam, somewhat poorly drained.

TextureLoama good balance for most vegetables
pH6.4slightly 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 farmland if drainedUSDA classification

Map unit: Conover loam, 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 48418; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Byron, MI

Summer high81 °Faverage high, July
Winter low15 °Faverage low, January
Hot days6days a year at 90 °F or more
Freezing nights149nights a year at 32 °F or less
Growing degree days2,422base 50 °F — the season’s usable heat
Longest day15 h 20 mindaylight on June 21
Shortest day9 h 01 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation33.6 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 30 °F, low 15 °F 30°15° JanFebruary: average high 33 °F, low 15 °F 33°15° FebMarch: average high 42 °F, low 24 °F 42°24° MarApril: average high 55 °F, low 34 °F 55°34° AprMay: average high 68 °F, low 46 °F 68°46° MayJune: average high 77 °F, low 55 °F 77°55° JunJuly: average high 81 °F, low 59 °F 81°59° JulAugust: average high 79 °F, low 58 °F 79°58° AugSeptember: average high 72 °F, low 50 °F 72°50° SepOctober: average high 59 °F, low 40 °F 59°40° OctNovember: average high 47 °F, low 30 °F 47°30° NovDecember: average high 34 °F, low 21 °F 34°21° Dec

Precipitation by month inches

0″1″2″3″4″January: 2.04 in precipitation 2.0 JanFebruary: 2.05 in precipitation 2.0 FebMarch: 2.06 in precipitation 2.1 MarApril: 2.95 in precipitation 3.0 AprMay: 3.82 in precipitation 3.8 MayJune: 3.19 in precipitation 3.2 JunJuly: 3.72 in precipitation 3.7 JulAugust: 3.37 in precipitation 3.4 AugSeptember: 2.96 in precipitation 3.0 SepOctober: 2.88 in precipitation 2.9 OctNovember: 2.52 in precipitation 2.5 NovDecember: 2.07 in precipitation 2.1 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Linden Wwtp, MI (9 mi away); precipitation: Fenton 6.2 Wsw, MI (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

488166a
Cohoctah, MI · 2 mi
484146a
Bancroft, MI · 7 mi
484366a
Gaines, MI · 7 mi
484296a
Durand, MI · 8 mi
484516a
Linden, MI · 8 mi
488556a
Howell, MI · 9 mi
488576a
Morrice, MI · 10 mi
488366a
Fowlerville, MI · 10 mi

Michigan planting zones →

Questions about 48418

What planting zone is ZIP code 48418?

ZIP code 48418 (Byron, MI) is in USDA hardiness zone 6a on the 2023 map: the coldest night of an average winter reaches −10 to −5 °F (−23.3 to −20.6 °C).

When is the last frost in Byron, MI?

The median last spring frost (32 °F) near 48418 is May 3; after May 20 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Linden Wwtp station.

When is the first frost in Byron, MI?

The median first fall frost near 48418 is October 12, giving a median frost-free growing season of 161 days.

When should I plant tomatoes in 48418?

Start tomato seeds indoors around Mar 8 – Mar 22 and set transplants outside around May 10 – May 24, one to three weeks after the median last frost.

How much rain and snow does 48418 get?

About 33.6 inches of precipitation a year (NOAA 1991–2020 normals, Fenton 6.2 Wsw station).

How hot do summers get in Byron, MI?

The average high peaks at 81 °F in July, with about 6 days a year at 90 °F or more.

What kind of soil does 48418 have?

The USDA soil survey maps Conover at the center of ZIP 48418: loam, somewhat poorly drained, pH about 6.4 (slightly acidic).

Did spring come early in Byron, MI in 2026?

Spring leaf-out near 48418 came on Apr 2 in 2026, 9 days earlier than the 1991–2020 average (Apr 11), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Byron, MI?

Long-day onions: the longest day near 48418 is 15 h 20 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).