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

Planting zone for 48663 — Saginaw, MI

ZIP code 48663 (Saginaw, Saginaw County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is April 29 and the first fall frost October 21.

Where ZIP 48663 is

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 29

First frostOct 21

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 Saginaw, 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 Saginaw, MI

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 29median — 50% chance of a later frost

Safe for tender plantsMay 13only 10% chance of frost after

First fall frostOctober 21median — 10% chance by Oct 5

Growing season175 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 17 and returns around November 3.

From the NOAA station Saginaw #3, MI — within 1 mile, elevation 600 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 48663

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 18 – Apr 1

SpinachSow outdoors · Mar 18 – Apr 8

Broccoli, cabbageStart indoors · Feb 18 – Mar 4

Broccoli, cabbageTransplant · Apr 8 – Apr 22

Onion setsPlant outdoors · Apr 1 – Apr 15

PotatoesPlant outdoors · Apr 8 – Apr 22

LettuceSow outdoors · Apr 1 – Apr 15

Carrots, beetsSow outdoors · Apr 8 – Apr 22

TomatoesStart indoors · Mar 4 – Mar 18

TomatoesTransplant · May 6 – May 20

Peppers, eggplantStart indoors · Feb 18 – Mar 4

Peppers, eggplantTransplant · May 13 – May 27

BeansSow outdoors · May 6 – May 20

Sweet cornSow outdoors · May 6 – May 20

Cucumbers, squashSow outdoors · May 6 – May 20

Fall lettuce, spinachSow outdoors · Aug 26 – Sep 9

GarlicPlant cloves · Oct 7 – Nov 11

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 29) and first fall frost (Oct 21) 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 48663 came on Apr 11 — about the same time as the 1991–2020 average (Apr 12).

average
Apr 122026
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 Saginaw, MI.

Soil in Saginaw, MI

The center of ZIP 48663 is mapped as Water: built-over ground without natural soil data. Garden soil here is usually imported or disturbed — test before you plant.

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 48663; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Saginaw, MI

Summer high83 °Faverage high, July

Winter low16 °Faverage low, January

Hot days13days a year at 90 °F or more

Freezing nights143nights a year at 32 °F or less

Growing degree days2,779base 50 °F — the season’s usable heat

Longest day15 h 25 mindaylight on June 21

Shortest day8 h 57 mindaylight on December 21

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

Precipitation34 inper year, rain and melted snow

Snowfall41 inper year

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Saginaw #3, MI (within 1 mile); precipitation: Saginaw #3, MI (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

Carrollton, MI · 3 mi

All 11 ZIP codes in Saginaw → · Michigan planting zones →

Questions about 48663

What planting zone is ZIP code 48663?

ZIP code 48663 (Saginaw, 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 Saginaw, MI?

The median last spring frost (32 °F) near 48663 is April 29; after May 13 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Saginaw #3 station.

When is the first frost in Saginaw, MI?

The median first fall frost near 48663 is October 21, giving a median frost-free growing season of 175 days.

When should I plant tomatoes in 48663?

Start tomato seeds indoors around Mar 4 – Mar 18 and set transplants outside around May 6 – May 20, one to three weeks after the median last frost.

How much rain and snow does 48663 get?

About 34 inches of precipitation a year and 41 inches of snowfall (NOAA 1991–2020 normals, Saginaw #3 station).

How hot do summers get in Saginaw, MI?

The average high peaks at 83 °F in July, with about 13 days a year at 90 °F or more.

Did spring come early in Saginaw, MI in 2026?

Spring leaf-out near 48663 came on Apr 11 in 2026, about the same as the 1991–2020 average (Apr 12), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Saginaw, MI?

Long-day onions: the longest day near 48663 is 15 h 25 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).