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

Planting zone for 48074 — Smiths Creek, MI

ZIP code 48074 (Smiths Creek, St. Clair County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is April 19 and the first fall frost November 3.

Where ZIP 48074 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 frostApr 19

First frostNov 3

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 Smiths Creek, 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 Smiths Creek, MI

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 19median — 50% chance of a later frost

Safe for tender plantsMay 4only 10% chance of frost after

First fall frostNovember 3median — 10% chance by Oct 20

Growing season196 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 7 and returns around November 12.

From the NOAA station Port Huron, MI — 7 miles away, elevation 591 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 48074

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 8 – Mar 22

SpinachSow outdoors · Mar 8 – Mar 29

Broccoli, cabbageStart indoors · Feb 8 – Feb 22

Broccoli, cabbageTransplant · Mar 29 – Apr 12

Onion setsPlant outdoors · Mar 22 – Apr 5

PotatoesPlant outdoors · Mar 29 – Apr 12

LettuceSow outdoors · Mar 22 – Apr 5

Carrots, beetsSow outdoors · Mar 29 – Apr 12

TomatoesStart indoors · Feb 22 – Mar 8

TomatoesTransplant · Apr 26 – May 10

Peppers, eggplantStart indoors · Feb 8 – Feb 22

Peppers, eggplantTransplant · May 3 – May 17

BeansSow outdoors · Apr 26 – May 10

Sweet cornSow outdoors · Apr 26 – May 10

Cucumbers, squashSow outdoors · Apr 26 – May 10

Fall lettuce, spinachSow outdoors · Sep 8 – Sep 22

GarlicPlant cloves · Oct 20 – Nov 24

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 19) and first fall frost (Nov 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 48074 came on Apr 11 — about the same time as the 1991–2020 average (Apr 13).

average
Apr 132026
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.

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 Smiths Creek, MI.

Soil in Smiths Creek, MI

The soil mapped at the center of ZIP 48074 is Allendale — loamy fine sand, somewhat poorly drained.

TextureLoamy fine sanddrains and warms fast; dries out and needs more feeding

pH5.8moderately acidic; most vegetables like 6.0–7.0

DrainageSomewhat poorly drainedconsider raised beds

Organic matter2.25%moderate

Hydrologic groupDwater soaks in very slowly

Farmland classFarmland of local importanceUSDA classification

Map unit: Allendale-Hoytville complex, 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 48074; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Smiths Creek, MI

Summer high81 °Faverage high, July

Winter low20 °Faverage low, January

Hot days10days a year at 90 °F or more

Freezing nights122nights a year at 32 °F or less

Growing degree days2,898base 50 °F — the season’s usable heat

Longest day15 h 21 mindaylight on June 21

Shortest day9 h 00 mindaylight on December 21

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

Precipitation34.5 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: Port Huron, MI (7 mi away); precipitation: Port Huron 1.6 W, MI (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

480406a

Marysville, MI · 5 mi

480606b

Port Huron, MI · 6 mi

480496a

North Street, MI · 6 mi

480796a

Saint Clair, MI · 6 mi

480276a

Goodells, MI · 7 mi

480616b

Port Huron, MI · 7 mi

480636a

Columbus, MI · 9 mi

480046b

Anchorville, MI · 10 mi

Michigan planting zones →

Questions about 48074

What planting zone is ZIP code 48074?

ZIP code 48074 (Smiths Creek, 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 Smiths Creek, MI?

The median last spring frost (32 °F) near 48074 is April 19; after May 4 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Port Huron station.

When is the first frost in Smiths Creek, MI?

The median first fall frost near 48074 is November 3, giving a median frost-free growing season of 196 days.

When should I plant tomatoes in 48074?

Start tomato seeds indoors around Feb 22 – Mar 8 and set transplants outside around Apr 26 – May 10, one to three weeks after the median last frost.

How much rain and snow does 48074 get?

About 34.5 inches of precipitation a year (NOAA 1991–2020 normals, Port Huron 1.6 W station).

How hot do summers get in Smiths Creek, MI?

The average high peaks at 81 °F in July, with about 10 days a year at 90 °F or more.

What kind of soil does 48074 have?

The USDA soil survey maps Allendale at the center of ZIP 48074: loamy fine sand, somewhat poorly drained, pH about 5.8 (moderately acidic).

Did spring come early in Smiths Creek, MI in 2026?

Spring leaf-out near 48074 came on Apr 11 in 2026, about the same as the 1991–2020 average (Apr 13), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Smiths Creek, MI?

Long-day onions: the longest day near 48074 is 15 h 21 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).