Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 48649 — Oakley, MI

ZIP code 48649 (Oakley, Saginaw County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is May 1 and the first fall frost October 15.

Where ZIP 48649 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 1

First frostOct 15

2012 zone5b

Was 5b 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 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Oakley, 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 Oakley, 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 17only 10% chance of frost after

First fall frostOctober 15median — 10% chance by Oct 1

Growing season164 daysfrost-free, median

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

From the NOAA station Owosso Wwtp, MI — 9 miles away, elevation 732 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 48649

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 48649 came on Apr 4 — 8 days earlier than the 1991–2020 average (Apr 12).

average
Apr 122026
Apr 4

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.

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 Oakley, MI.

Soil in Oakley, MI

The soil mapped at the center of ZIP 48649 is Conover — loam, somewhat poorly drained.

TextureLoama good balance for most vegetables

pH6.8neutral; most vegetables like 6.0–7.0

DrainageSomewhat poorly drainedconsider raised beds

Organic matter2.8%moderate

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classPrime farmland if drainedUSDA classification

Map unit: Conover-Williamstown loams, 0 to 6 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 48649; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Oakley, MI

Summer high82 °Faverage high, July

Winter low16 °Faverage low, January

Hot days8days a year at 90 °F or more

Freezing nights149nights a year at 32 °F or less

Growing degree days2,599base 50 °F — the season’s usable heat

Longest day15 h 23 mindaylight on June 21

Shortest day8 h 59 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation34.3 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Owosso Wwtp, MI (9 mi away); precipitation: Chesaning, MI (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

Saint Charles, MI · 10 mi

484606a

New Lothrop, MI · 12 mi

Michigan planting zones →

Questions about 48649

What planting zone is ZIP code 48649?

ZIP code 48649 (Oakley, 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 Oakley, MI?

The median last spring frost (32 °F) near 48649 is May 1; after May 17 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Owosso Wwtp station.

When is the first frost in Oakley, MI?

The median first fall frost near 48649 is October 15, giving a median frost-free growing season of 164 days.

When should I plant tomatoes in 48649?

Start tomato seeds indoors around Mar 6 – Mar 20 and set transplants outside around May 8 – May 22, one to three weeks after the median last frost.

How much rain and snow does 48649 get?

About 34.3 inches of precipitation a year (NOAA 1991–2020 normals, Chesaning station).

How hot do summers get in Oakley, MI?

The average high peaks at 82 °F in July, with about 8 days a year at 90 °F or more.

What kind of soil does 48649 have?

The USDA soil survey maps Conover at the center of ZIP 48649: loam, somewhat poorly drained, pH about 6.8 (neutral).

Did spring come early in Oakley, MI in 2026?

Spring leaf-out near 48649 came on Apr 4 in 2026, 8 days earlier than the 1991–2020 average (Apr 12), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Oakley, MI?

Long-day onions: the longest day near 48649 is 15 h 23 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 48649 change?

Yes. The 2012 USDA map put 48649 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.