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

Planting zone for 46365 — Mill Creek, IN

ZIP code 46365 (Mill Creek, LaPorte 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 October 27.

Where ZIP 46365 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 frostOct 27

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 Mill Creek, IN…

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 Mill Creek, IN

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 3only 10% chance of frost after

First fall frostOctober 27median — 10% chance by Oct 14

Growing season191 daysfrost-free, median

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

From the NOAA station Laporte, IN — 9 miles away, elevation 810 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 46365

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 1 – Sep 15

GarlicPlant cloves · Oct 13 – Nov 17

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 19) and first fall frost (Oct 27) 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 46365 came on Mar 21 — 15 days earlier than the 1991–2020 average (Apr 5).

average
Apr 52026
Mar 21

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 Indiana

558 plants native to the lower 48 states, recorded in Indiana, 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 Mill Creek, IN.

Soil in Mill Creek, IN

The soil mapped at the center of ZIP 46365 is Tracy — sandy loam, well drained.

TextureSandy loamdrains and warms fast; dries out and needs more feeding

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

DrainageWell drainednatural drainage class

Organic matter1.5%low — add compost

Hydrologic groupBwater soaks in moderately

Farmland classNot prime farmlandUSDA classification

Map unit: Tracy sandy loam, 6 to 12 percent slopes, moderately eroded.

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 46365; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Mill Creek, IN

Summer high82 °Faverage high, July

Winter low17 °Faverage low, January

Hot days10days a year at 90 °F or more

Freezing nights119nights a year at 32 °F or less

Growing degree days3,052base 50 °F — the season’s usable heat

Longest day15 h 12 mindaylight on June 21

Shortest day9 h 09 mindaylight on December 21

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

Precipitation40.5 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: Laporte, IN (9 mi away); precipitation: La Porte 2.3 Ese, IN (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

463716a

Rolling Prairie, IN · 6 mi

465546a

North Liberty, IN · 7 mi

465526a

New Carlisle, IN · 8 mi

South Bend, IN · 11 mi

463526a

La Porte, IN · 11 mi

Indiana planting zones →

Questions about 46365

What planting zone is ZIP code 46365?

ZIP code 46365 (Mill Creek, IN) 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 Mill Creek, IN?

The median last spring frost (32 °F) near 46365 is April 19; after May 3 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Laporte station.

When is the first frost in Mill Creek, IN?

The median first fall frost near 46365 is October 27, giving a median frost-free growing season of 191 days.

When should I plant tomatoes in 46365?

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 46365 get?

About 40.5 inches of precipitation a year (NOAA 1991–2020 normals, La Porte 2.3 Ese station).

How hot do summers get in Mill Creek, IN?

The average high peaks at 82 °F in July, with about 10 days a year at 90 °F or more.

What kind of soil does 46365 have?

The USDA soil survey maps Tracy at the center of ZIP 46365: sandy loam, well drained, pH about 5.8 (moderately acidic).

Did spring come early in Mill Creek, IN in 2026?

Spring leaf-out near 46365 came on Mar 21 in 2026, 15 days earlier than the 1991–2020 average (Apr 5), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Mill Creek, IN?

Long-day onions: the longest day near 46365 is 15 h 12 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 46365 change?

Yes. The 2012 USDA map put 46365 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.