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

Planting zone for 46382 — Union Mills, IN

ZIP code 46382 (Union Mills, LaPorte County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is April 29 and the first fall frost October 13.

Where ZIP 46382 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 frostApr 29
First frostOct 13
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 Union Mills, 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 Union Mills, IN

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 14only 10% chance of frost after
First fall frostOctober 13median — 10% chance by Oct 1
Growing season166 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 17 and returns around October 25.

From the NOAA station Wanatah 2 Wnw, IN — 9 miles away, elevation 735 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 46382

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 18 – Sep 1
GarlicPlant cloves · Sep 29 – Nov 3
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 29) and first fall frost (Oct 13) 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 46382 came on Mar 21 — 15 days earlier than the 1991–2020 average (Apr 5).

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 Indiana

533 plants native to the lower 48 states, recorded in Indiana, and rated by the USDA to survive −15 °F or colder — the bottom of zone 5b. Each links to its USDA PLANTS profile.

Trees 70

American basswood100 ft · blooms late spring · low shade tolerance · to −46 °FAmerican beech80 ft · blooms mid spring · low shade tolerance · to −44 °FAmerican chestnut115 ft · blooms early summer · high shade tolerance · to −33 °FAmerican elm120 ft · blooms early spring · medium shade tolerance · to −46 °FAmerican sycamore100 ft · blooms spring · medium shade tolerance · to −34 °Farborvitae50 ft · blooms mid spring · medium shade tolerance · to −33 °F

Shrubs 99

alderleaf buckthorn3 ft · blooms late spring · low shade tolerance · to −33 °FAllegheny serviceberry35 ft · blooms early spring · low shade tolerance · to −38 °Falternateleaf dogwood25 ft · blooms mid spring · low shade tolerance · to −47 °FAmerican black currant3 ft · blooms early spring · to −46 °FAmerican hazelnut10 ft · blooms spring · medium shade tolerance · to −33 °FAmerican holly40 ft · blooms mid spring · low shade tolerance · to −20 °F

Wildflowers & perennials 191

American bur-reed3 ft · blooms indeterminate · medium shade tolerance · to −33 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °FAmerican licorice4 ft · blooms late spring · medium shade tolerance · to −38 °FAmerican lotus3 ft · blooms mid summer · high shade tolerance · to −36 °FAmerican pokeweed7 ft · blooms mid summer · low shade tolerance · to −33 °FAmerican speedwell0.8 ft · blooms mid summer · low shade tolerance · to −38 °F

Grasses 156

American beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °Farctic brome3 ft · blooms early summer · low shade tolerance · to −33 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °Fbeaked spikerush3 ft · blooms late spring · high shade tolerance · to −28 °FBebb's sedge3 ft · blooms late spring · low shade tolerance · to −38 °FBicknell's sedge3 ft · blooms late spring · low shade tolerance · to −38 °F

Vines 7

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °Ffrost grape83 ft · blooms late spring · medium shade tolerance · to −23 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Fsummer grape30 ft · blooms late spring · low shade tolerance · to −23 °Ftrumpet honeysuckle16 ft · blooms late summer · low shade tolerance · to −33 °F

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 Union Mills, IN.

Soil in Union Mills, IN

The soil mapped at the center of ZIP 46382 is Hanna — sandy loam, moderately well drained.

TextureSandy loamdrains and warms fast; dries out and needs more feeding
pH6.2slightly acidic; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter2%moderate
Hydrologic groupCwater soaks in slowly
Farmland classprime farmlandUSDA classification

Map unit: Hanna sandy loam, 0 to 3 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 46382; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Union Mills, IN

Summer high83 °Faverage high, July
Winter low15 °Faverage low, January
Hot days17days a year at 90 °F or more
Freezing nights147nights a year at 32 °F or less
Growing degree days2,944base 50 °F — the season’s usable heat
Longest day15 h 11 mindaylight on June 21
Shortest day9 h 10 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation38.9 inper year, rain and melted snow
Snowfall42 inper year; 58 days with snow on the ground

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 32 °F, low 15 °F 32°15° JanFebruary: average high 35 °F, low 18 °F 35°18° FebMarch: average high 47 °F, low 27 °F 47°27° MarApril: average high 59 °F, low 37 °F 59°37° AprMay: average high 71 °F, low 49 °F 71°49° MayJune: average high 80 °F, low 59 °F 80°59° JunJuly: average high 83 °F, low 62 °F 83°62° JulAugust: average high 81 °F, low 59 °F 81°59° AugSeptember: average high 76 °F, low 51 °F 76°51° SepOctober: average high 63 °F, low 41 °F 63°41° OctNovember: average high 49 °F, low 31 °F 49°31° NovDecember: average high 37 °F, low 22 °F 37°22° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″January: 2.45 in precipitation, 13.8 in snowfall 2.5❄14 JanFebruary: 2.00 in precipitation, 9.4 in snowfall 2.0❄9 FebMarch: 2.51 in precipitation, 5.1 in snowfall 2.5❄5 MarApril: 3.52 in precipitation, 0.7 in snowfall 3.5❄1 AprMay: 3.91 in precipitation 3.9 MayJune: 3.99 in precipitation 4.0 JunJuly: 4.22 in precipitation 4.2 JulAugust: 3.68 in precipitation 3.7 AugSeptember: 3.38 in precipitation 3.4 SepOctober: 3.95 in precipitation, 0.1 in snowfall 4.0 OctNovember: 2.80 in precipitation, 1.3 in snowfall 2.8❄1 NovDecember: 2.49 in precipitation, 11.3 in snowfall 2.5❄11 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Wanatah 2 Wnw, IN (9 mi away); precipitation: Kingsbury 1n, IN (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

463465b
Kingsford Heights, IN · 4 mi
463526a
La Porte, IN · 4 mi
463405b
Hanna, IN · 5 mi
463456a
Kingsbury, IN · 6 mi
463905b
Wanatah, IN · 7 mi
465325b
Hamlet, IN · 8 mi
463506a
La Porte, IN · 10 mi
463916a
Westville, IN · 10 mi

Indiana planting zones →

Questions about 46382

What planting zone is ZIP code 46382?

ZIP code 46382 (Union Mills, IN) 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 Union Mills, IN?

The median last spring frost (32 °F) near 46382 is April 29; after May 14 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Wanatah 2 Wnw station.

When is the first frost in Union Mills, IN?

The median first fall frost near 46382 is October 13, giving a median frost-free growing season of 166 days.

When should I plant tomatoes in 46382?

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 46382 get?

About 38.9 inches of precipitation a year and 42 inches of snowfall (NOAA 1991–2020 normals, Kingsbury 1n station).

How hot do summers get in Union Mills, IN?

The average high peaks at 83 °F in July, with about 17 days a year at 90 °F or more.

What kind of soil does 46382 have?

The USDA soil survey maps Hanna at the center of ZIP 46382: sandy loam, moderately well drained, pH about 6.2 (slightly acidic).

Did spring come early in Union Mills, IN in 2026?

Spring leaf-out near 46382 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 Union Mills, IN?

Long-day onions: the longest day near 46382 is 15 h 11 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).