Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 30, 2026

Planting zone for 49776 — Posen, MI

ZIP code 49776 (Posen, Presque Isle County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is May 13 and the first fall frost October 3.

Where ZIP 49776 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.

Zone5b−15 to −10 °F

Coldest night−26.1 to −23.3 °C

Last frostMay 13

First frostOct 3

2012 zone5b

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 5b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Posen, 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 Posen, MI

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostMay 13median — 50% chance of a later frost

Safe for tender plantsMay 30only 10% chance of frost after

First fall frostOctober 3median — 10% chance by Sep 22

Growing season141 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 1 and returns around October 14.

From the NOAA station Alpena 10nw, MI — 6 miles away, elevation 742 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 49776

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 1 – Apr 15

SpinachSow outdoors · Apr 1 – Apr 22

Broccoli, cabbageStart indoors · Mar 4 – Mar 18

Broccoli, cabbageTransplant · Apr 22 – May 6

Onion setsPlant outdoors · Apr 15 – Apr 29

PotatoesPlant outdoors · Apr 22 – May 6

LettuceSow outdoors · Apr 15 – Apr 29

Carrots, beetsSow outdoors · Apr 22 – May 6

TomatoesStart indoors · Mar 18 – Apr 1

TomatoesTransplant · May 20 – Jun 3

Peppers, eggplantStart indoors · Mar 4 – Mar 18

Peppers, eggplantTransplant · May 27 – Jun 10

BeansSow outdoors · May 20 – Jun 3

Sweet cornSow outdoors · May 20 – Jun 3

Cucumbers, squashSow outdoors · May 20 – Jun 3

Fall lettuce, spinachSow outdoors · Aug 8 – Aug 22

GarlicPlant cloves · Sep 19 – Oct 24

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 13) and first fall frost (Oct 3) 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 49776 came on Apr 19 — 4 days earlier than the 1991–2020 average (Apr 23).

average
Apr 232026
Apr 19

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 5b in Michigan

564 plants native to the lower 48 states, recorded in Michigan, and rated by the USDA to survive −15 °F or colder — the bottom of zone 5b. 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 Posen, MI.

Soil in Posen, MI

The soil mapped at the center of ZIP 49776 is Hagensville — fine sandy loam, somewhat poorly drained.

TextureFine sandy loamdrains and warms fast; dries out and needs more feeding

pH7.2neutral; most vegetables like 6.0–7.0

DrainageSomewhat poorly drainedconsider raised beds

Organic matter2.5%moderate

Hydrologic groupB/Dmoderate when drained; wet otherwise

Farmland classPrime farmland if drainedUSDA classification

Map unit: Hagensville fine sandy loam, 2 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 49776; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Posen, MI

Summer high80 °Faverage high, August

Winter low10 °Faverage low, February

Hot days9days a year at 90 °F or more

Freezing nights174nights a year at 32 °F or less

Growing degree days1,977base 50 °F — the season’s usable heat

Longest day15 h 39 mindaylight on June 21

Shortest day8 h 44 mindaylight on December 21

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

Precipitation29.7 inper year, rain and melted snow

Snowfall78 inper year; 109 days with snow on the ground

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Alpena 10nw, MI (6 mi away); precipitation: Alpena Co. Regional Airport, MI (12 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

497776a

Presque Isle, MI · 10 mi

497435a

Hawks, MI · 11 mi

497796a

Rogers City, MI · 14 mi

Michigan planting zones →

Questions about 49776

What planting zone is ZIP code 49776?

ZIP code 49776 (Posen, MI) is in USDA hardiness zone 5b on the 2023 map: the coldest night of an average winter reaches −15 to −10 °F (−26.1 to −23.3 °C).

When is the last frost in Posen, MI?

The median last spring frost (32 °F) near 49776 is May 13; after May 30 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Alpena 10nw station.

When is the first frost in Posen, MI?

The median first fall frost near 49776 is October 3, giving a median frost-free growing season of 141 days.

When should I plant tomatoes in 49776?

Start tomato seeds indoors around Mar 18 – Apr 1 and set transplants outside around May 20 – Jun 3, one to three weeks after the median last frost.

How much rain and snow does 49776 get?

About 29.7 inches of precipitation a year and 78 inches of snowfall (NOAA 1991–2020 normals, Alpena Co. Regional Airport station).

How hot do summers get in Posen, MI?

The average high peaks at 80 °F in August, with about 9 days a year at 90 °F or more.

What kind of soil does 49776 have?

The USDA soil survey maps Hagensville at the center of ZIP 49776: fine sandy loam, somewhat poorly drained, pH about 7.2 (neutral).

Did spring come early in Posen, MI in 2026?

Spring leaf-out near 49776 came on Apr 19 in 2026, 4 days earlier than the 1991–2020 average (Apr 23), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Posen, MI?

Long-day onions: the longest day near 49776 is 15 h 39 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).