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

Planting zone for 46537 — Lapaz, IN

ZIP code 46537 (Lapaz, Marshall County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is May 1 and the first fall frost October 13.

Where ZIP 46537 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 frostMay 1
First frostOct 13
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 Lapaz, 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 Lapaz, IN

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 1median — 50% chance of a later frost
Safe for tender plantsMay 18only 10% chance of frost after
First fall frostOctober 13median — 10% chance by Sep 30
Growing season163 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 21 and returns around October 26.

From the NOAA station Lakeville, IN — 5 miles away, elevation 840 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 46537

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 20 – Apr 3
SpinachSow outdoors · Mar 20 – Apr 10
Broccoli, cabbageStart indoors · Feb 20 – Mar 6
Broccoli, cabbageTransplant · Apr 10 – Apr 24
Onion setsPlant outdoors · Apr 3 – Apr 17
PotatoesPlant outdoors · Apr 10 – Apr 24
LettuceSow outdoors · Apr 3 – Apr 17
Carrots, beetsSow outdoors · Apr 10 – Apr 24
TomatoesStart indoors · Mar 6 – Mar 20
TomatoesTransplant · May 8 – May 22
Peppers, eggplantStart indoors · Feb 20 – Mar 6
Peppers, eggplantTransplant · May 15 – May 29
BeansSow outdoors · May 8 – May 22
Sweet cornSow outdoors · May 8 – May 22
Cucumbers, squashSow outdoors · May 8 – May 22
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 (May 1) 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 46537 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 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.

Trees 71

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 105

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 200

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 161

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 9

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °Fcatbird grape30 ft · blooms late spring · medium shade tolerance · to −13 °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 °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 Lapaz, IN.

Soil in Lapaz, IN

The soil mapped at the center of ZIP 46537 is Riddles — fine sandy loam, well drained.

TextureFine sandy loamdrains and warms fast; dries out and needs more feeding
pH6.5neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter1.5%low — add compost
Hydrologic groupBwater soaks in moderately
Farmland classprime farmlandUSDA classification

Map unit: Riddles-Oshtemo fine sandy loams, 1 to 5 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 46537; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Lapaz, IN

Summer high82 °Faverage high, July
Winter low15 °Faverage low, January
Hot days7days a year at 90 °F or more
Freezing nights140nights a year at 32 °F or less
Growing degree days2,755base 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)
Precipitation40.9 inper year, rain and melted snow

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 31 °F, low 15 °F 31°15° JanFebruary: average high 35 °F, low 17 °F 35°17° FebMarch: average high 46 °F, low 26 °F 46°26° MarApril: average high 59 °F, low 36 °F 59°36° AprMay: average high 70 °F, low 47 °F 70°47° MayJune: average high 79 °F, low 57 °F 79°57° JunJuly: average high 82 °F, low 61 °F 82°61° JulAugust: average high 80 °F, low 58 °F 80°58° AugSeptember: average high 75 °F, low 51 °F 75°51° SepOctober: average high 62 °F, low 40 °F 62°40° OctNovember: average high 48 °F, low 30 °F 48°30° NovDecember: average high 37 °F, low 21 °F 37°21° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 2.71 in precipitation 2.7 JanFebruary: 2.39 in precipitation 2.4 FebMarch: 2.47 in precipitation 2.5 MarApril: 3.57 in precipitation 3.6 AprMay: 4.42 in precipitation 4.4 MayJune: 4.16 in precipitation 4.2 JunJuly: 4.24 in precipitation 4.2 JulAugust: 4.15 in precipitation 4.2 AugSeptember: 3.55 in precipitation 3.5 SepOctober: 3.71 in precipitation 3.7 OctNovember: 3.05 in precipitation 3.0 NovDecember: 2.48 in precipitation 2.5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Lakeville, IN (5 mi away); precipitation: Walkerton 5.7 Ene, IN (5 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

465366a
Lakeville, IN · 4 mi
465726a
Tyner, IN · 6 mi
465066a
Bremen, IN · 7 mi
465636a
Plymouth, IN · 7 mi
465956a
Wyatt, IN · 9 mi
465546a
North Liberty, IN · 9 mi
465746a
Walkerton, IN · 9 mi
466346a
South Bend, IN · 10 mi

Indiana planting zones →

Questions about 46537

What planting zone is ZIP code 46537?

ZIP code 46537 (Lapaz, 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 Lapaz, IN?

The median last spring frost (32 °F) near 46537 is May 1; after May 18 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Lakeville station.

When is the first frost in Lapaz, IN?

The median first fall frost near 46537 is October 13, giving a median frost-free growing season of 163 days.

When should I plant tomatoes in 46537?

Start tomato seeds indoors around Mar 6 – Mar 20 and set transplants outside around May 8 – May 22, one to three weeks after the median last frost.

How much rain and snow does 46537 get?

About 40.9 inches of precipitation a year (NOAA 1991–2020 normals, Walkerton 5.7 Ene station).

How hot do summers get in Lapaz, IN?

The average high peaks at 82 °F in July, with about 7 days a year at 90 °F or more.

What kind of soil does 46537 have?

The USDA soil survey maps Riddles at the center of ZIP 46537: fine sandy loam, well drained, pH about 6.5 (neutral).

Did spring come early in Lapaz, IN in 2026?

Spring leaf-out near 46537 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 Lapaz, IN?

Long-day onions: the longest day near 46537 is 15 h 11 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 46537 change?

Yes. The 2012 USDA map put 46537 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.