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

Planting zone for 47174 — Sulphur, IN

ZIP code 47174 (Sulphur, Crawford County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 17 and the first fall frost October 19.

Where ZIP 47174 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.

Zone6b−5 to 0 °F
Coldest night−20.6 to −17.8 °C
Last frostApr 17
First frostOct 19
2012 zone6a

Was 6a 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 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Sulphur, 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 Sulphur, IN

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 17median — 50% chance of a later frost
Safe for tender plantsMay 4only 10% chance of frost after
First fall frostOctober 19median — 10% chance by Oct 6
Growing season184 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 3 and returns around October 31.

From the NOAA station English, IN — 4 miles away, elevation 509 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 47174

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 6 – Mar 20
SpinachSow outdoors · Mar 6 – Mar 27
Broccoli, cabbageStart indoors · Feb 6 – Feb 20
Broccoli, cabbageTransplant · Mar 27 – Apr 10
Onion setsPlant outdoors · Mar 20 – Apr 3
PotatoesPlant outdoors · Mar 27 – Apr 10
LettuceSow outdoors · Mar 20 – Apr 3
Carrots, beetsSow outdoors · Mar 27 – Apr 10
TomatoesStart indoors · Feb 20 – Mar 6
TomatoesTransplant · Apr 24 – May 8
Peppers, eggplantStart indoors · Feb 6 – Feb 20
Peppers, eggplantTransplant · May 1 – May 15
BeansSow outdoors · Apr 24 – May 8
Sweet cornSow outdoors · Apr 24 – May 8
Cucumbers, squashSow outdoors · Apr 24 – May 8
Fall lettuce, spinachSow outdoors · Aug 24 – Sep 7
GarlicPlant cloves · Oct 5 – Nov 9
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 17) and first fall frost (Oct 19) 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 47174 came on Mar 3 — 8 days earlier than the 1991–2020 average (Mar 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 6b in Indiana

564 plants native to the lower 48 states, recorded in Indiana, and rated by the USDA to survive −5 °F or colder — the bottom of zone 6b. Each links to its USDA PLANTS profile.

Trees 72

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 202

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 162

American beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °Farctic brome3 ft · blooms early summer · low shade tolerance · to −33 °Fautumn bluegrass1.5 ft · blooms late spring · medium shade tolerance · to −8 °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 °F

Vines 11

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 °Fgraybark grape50 ft · blooms late spring · medium shade tolerance · to −8 °Fheartleaf peppervine2 ft · blooms late spring · low shade tolerance · to −8 °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 Sulphur, IN.

Soil in Sulphur, IN

The soil mapped at the center of ZIP 47174 is Apalona — silt loam, moderately well drained.

TextureSilt loama good balance for most vegetables
pH5.9moderately acidic; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter2%moderate
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classprime farmlandUSDA classification

Map unit: Apalona-Zanesville silt loams, 2 to 6 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 47174; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Sulphur, IN

Summer high88 °Faverage high, July
Winter low24 °Faverage low, January
Hot days31days a year at 90 °F or more
Freezing nights110nights a year at 32 °F or less
Growing degree days4,097base 50 °F — the season’s usable heat
Longest day14 h 50 mindaylight on June 21
Shortest day9 h 30 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation51 inper year, rain and melted snow

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 43 °F, low 24 °F 43°24° JanFebruary: average high 48 °F, low 26 °F 48°26° FebMarch: average high 58 °F, low 35 °F 58°35° MarApril: average high 69 °F, low 44 °F 69°44° AprMay: average high 77 °F, low 54 °F 77°54° MayJune: average high 86 °F, low 62 °F 86°62° JunJuly: average high 88 °F, low 66 °F 88°66° JulAugust: average high 88 °F, low 64 °F 88°64° AugSeptember: average high 82 °F, low 56 °F 82°56° SepOctober: average high 71 °F, low 44 °F 71°44° OctNovember: average high 58 °F, low 35 °F 58°35° NovDecember: average high 47 °F, low 28 °F 47°28° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 3.77 in precipitation 3.8 JanFebruary: 3.64 in precipitation 3.6 FebMarch: 4.82 in precipitation 4.8 MarApril: 5.25 in precipitation 5.3 AprMay: 4.99 in precipitation 5.0 MayJune: 5.41 in precipitation 5.4 JunJuly: 3.81 in precipitation 3.8 JulAugust: 2.93 in precipitation 2.9 AugSeptember: 3.70 in precipitation 3.7 SepOctober: 4.01 in precipitation 4.0 OctNovember: 4.34 in precipitation 4.3 NovDecember: 4.31 in precipitation 4.3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: English, IN (4 mi away); precipitation: English, IN (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6b.

471236b
Grantsburg, IN · 4 mi
471186b
English, IN · 5 mi
471376b
Leavenworth, IN · 6 mi
475766b
Saint Croix, IN · 7 mi
475146b
Branchville, IN · 8 mi
475516b
Leopold, IN · 9 mi
471756b
Taswell, IN · 10 mi
471166b
Eckerty, IN · 10 mi

Indiana planting zones →

Questions about 47174

What planting zone is ZIP code 47174?

ZIP code 47174 (Sulphur, IN) is in USDA hardiness zone 6b on the 2023 map: the coldest night of an average winter reaches −5 to 0 °F (−20.6 to −17.8 °C).

When is the last frost in Sulphur, IN?

The median last spring frost (32 °F) near 47174 is April 17; after May 4 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, English station.

When is the first frost in Sulphur, IN?

The median first fall frost near 47174 is October 19, giving a median frost-free growing season of 184 days.

When should I plant tomatoes in 47174?

Start tomato seeds indoors around Feb 20 – Mar 6 and set transplants outside around Apr 24 – May 8, one to three weeks after the median last frost.

How much rain and snow does 47174 get?

About 51 inches of precipitation a year (NOAA 1991–2020 normals, English station).

How hot do summers get in Sulphur, IN?

The average high peaks at 88 °F in July, with about 31 days a year at 90 °F or more.

What kind of soil does 47174 have?

The USDA soil survey maps Apalona at the center of ZIP 47174: silt loam, moderately well drained, pH about 5.9 (moderately acidic).

Did spring come early in Sulphur, IN in 2026?

Spring leaf-out near 47174 came on Mar 3 in 2026, 8 days earlier than the 1991–2020 average (Mar 11), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Sulphur, IN?

Intermediate onions: the longest day near 47174 is 14 h 50 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 47174 change?

Yes. The 2012 USDA map put 47174 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.