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

Planting zone for 46742 — Hamilton, IN

ZIP code 46742 (Hamilton, Steuben County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is April 30 and the first fall frost October 16.

Where ZIP 46742 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 30

First frostOct 16

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 Hamilton, 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 Hamilton, IN

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 30median — 50% chance of a later frost

Safe for tender plantsMay 15only 10% chance of frost after

First fall frostOctober 16median — 10% chance by Oct 1

Growing season167 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 19 and returns around October 29.

From the NOAA station Angola, IN — 11 miles away, elevation 1,020 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 46742

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 19 – Apr 2

SpinachSow outdoors · Mar 19 – Apr 9

Broccoli, cabbageStart indoors · Feb 19 – Mar 5

Broccoli, cabbageTransplant · Apr 9 – Apr 23

Onion setsPlant outdoors · Apr 2 – Apr 16

PotatoesPlant outdoors · Apr 9 – Apr 23

LettuceSow outdoors · Apr 2 – Apr 16

Carrots, beetsSow outdoors · Apr 9 – Apr 23

TomatoesStart indoors · Mar 5 – Mar 19

TomatoesTransplant · May 7 – May 21

Peppers, eggplantStart indoors · Feb 19 – Mar 5

Peppers, eggplantTransplant · May 14 – May 28

BeansSow outdoors · May 7 – May 21

Sweet cornSow outdoors · May 7 – May 21

Cucumbers, squashSow outdoors · May 7 – May 21

Fall lettuce, spinachSow outdoors · Aug 21 – Sep 4

GarlicPlant cloves · Oct 2 – Nov 6

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 30) and first fall frost (Oct 16) 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 46742 came on Mar 22 — 15 days earlier than the 1991–2020 average (Apr 6).

average
Apr 62026
Mar 22

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 Hamilton, IN.

Soil in Hamilton, IN

The soil mapped at the center of ZIP 46742 is Pewamo — silty clay loam, very poorly drained.

TextureSilty clay loamholds water and nutrients; slow to drain and warm up

pH6.4slightly acidic; most vegetables like 6.0–7.0

DrainageVery poorly drainedconsider raised beds

Organic matter4%moderate

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classPrime farmland if drainedUSDA classification

Map unit: Pewamo silty clay loam, 0 to 1 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 46742; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Hamilton, IN

Summer high82 °Faverage high, July

Winter low16 °Faverage low, January

Hot days7days a year at 90 °F or more

Freezing nights145nights a year at 32 °F or less

Growing degree days2,721base 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)

Precipitation38.2 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: Angola, IN (11 mi away); precipitation: Angola 8.7 Ese, IN (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

435186a

Edon, OH · 7 mi

467796a

Pleasant Lake, IN · 8 mi

Indiana planting zones →

Questions about 46742

What planting zone is ZIP code 46742?

ZIP code 46742 (Hamilton, 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 Hamilton, IN?

The median last spring frost (32 °F) near 46742 is April 30; after May 15 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Angola station.

When is the first frost in Hamilton, IN?

The median first fall frost near 46742 is October 16, giving a median frost-free growing season of 167 days.

When should I plant tomatoes in 46742?

Start tomato seeds indoors around Mar 5 – Mar 19 and set transplants outside around May 7 – May 21, one to three weeks after the median last frost.

How much rain and snow does 46742 get?

About 38.2 inches of precipitation a year (NOAA 1991–2020 normals, Angola 8.7 Ese station).

How hot do summers get in Hamilton, 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 46742 have?

The USDA soil survey maps Pewamo at the center of ZIP 46742: silty clay loam, very poorly drained, pH about 6.4 (slightly acidic).

Did spring come early in Hamilton, IN in 2026?

Spring leaf-out near 46742 came on Mar 22 in 2026, 15 days earlier than the 1991–2020 average (Apr 6), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Hamilton, IN?

Long-day onions: the longest day near 46742 is 15 h 11 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 46742 change?

Yes. The 2012 USDA map put 46742 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.