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

Planting zone for 47371 — Portland, IN

ZIP code 47371 (Portland, Jay County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is April 28 and the first fall frost October 15.

Where ZIP 47371 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 28

First frostOct 15

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 Portland, 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 Portland, IN

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 28median — 50% chance of a later frost

Safe for tender plantsMay 14only 10% chance of frost after

First fall frostOctober 15median — 10% chance by Oct 1

Growing season171 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 15 and returns around October 28.

From the NOAA station Portland 1 Sw, IN — 2 miles away, elevation 909 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 47371

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 17 – Mar 31

SpinachSow outdoors · Mar 17 – Apr 7

Broccoli, cabbageStart indoors · Feb 17 – Mar 3

Broccoli, cabbageTransplant · Apr 7 – Apr 21

Onion setsPlant outdoors · Mar 31 – Apr 14

PotatoesPlant outdoors · Apr 7 – Apr 21

LettuceSow outdoors · Mar 31 – Apr 14

Carrots, beetsSow outdoors · Apr 7 – Apr 21

TomatoesStart indoors · Mar 3 – Mar 17

TomatoesTransplant · May 5 – May 19

Peppers, eggplantStart indoors · Feb 17 – Mar 3

Peppers, eggplantTransplant · May 12 – May 26

BeansSow outdoors · May 5 – May 19

Sweet cornSow outdoors · May 5 – May 19

Cucumbers, squashSow outdoors · May 5 – May 19

Fall lettuce, spinachSow outdoors · Aug 20 – Sep 3

GarlicPlant cloves · Oct 1 – Nov 5

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 28) and first fall frost (Oct 15) 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 47371 came on Mar 10 — 21 days earlier than the 1991–2020 average (Mar 31).

average
Mar 312026
Mar 10

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).

Soil in Portland, IN

The soil mapped at the center of ZIP 47371 is Blount — silt loam, somewhat poorly drained.

TextureSilt loama good balance for most vegetables

pH6.5neutral; most vegetables like 6.0–7.0

DrainageSomewhat poorly drainedconsider raised beds

Organic matter2.5%moderate

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classPrime farmland if drainedUSDA classification

Map unit: Blount-Glynwood, thin solum complex, 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 47371; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Portland, IN

Summer high84 °Faverage high, July

Winter low17 °Faverage low, January

Hot days13days a year at 90 °F or more

Freezing nights132nights a year at 32 °F or less

Growing degree days3,064base 50 °F — the season’s usable heat

Longest day15 h 04 mindaylight on June 21

Shortest day9 h 17 mindaylight on December 21

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

Precipitation39.9 inper year, rain and melted snow

Snowfall19 inper year

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Portland 1 Sw, IN (2 mi away); precipitation: Portland 1 Sw, IN (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

Ridgeville, IN · 10 mi

473696a

Pennville, IN · 11 mi

458466a

Fort Recovery, OH · 11 mi

Indiana planting zones →

Questions about 47371

What planting zone is ZIP code 47371?

ZIP code 47371 (Portland, 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 Portland, IN?

The median last spring frost (32 °F) near 47371 is April 28; after May 14 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Portland 1 Sw station.

When is the first frost in Portland, IN?

The median first fall frost near 47371 is October 15, giving a median frost-free growing season of 171 days.

When should I plant tomatoes in 47371?

Start tomato seeds indoors around Mar 3 – Mar 17 and set transplants outside around May 5 – May 19, one to three weeks after the median last frost.

How much rain and snow does 47371 get?

About 39.9 inches of precipitation a year and 19 inches of snowfall (NOAA 1991–2020 normals, Portland 1 Sw station).

How hot do summers get in Portland, IN?

The average high peaks at 84 °F in July, with about 13 days a year at 90 °F or more.

What kind of soil does 47371 have?

The USDA soil survey maps Blount at the center of ZIP 47371: silt loam, somewhat poorly drained, pH about 6.5 (neutral).

Did spring come early in Portland, IN in 2026?

Spring leaf-out near 47371 came on Mar 10 in 2026, 21 days earlier than the 1991–2020 average (Mar 31), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Portland, IN?

Long-day onions: the longest day near 47371 is 15 h 04 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 47371 change?

Yes. The 2012 USDA map put 47371 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.