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

Planting zone for 50207 — New Sharon, IA

ZIP code 50207 (New Sharon, Mahaska County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is April 21 and the first fall frost October 16.

Where ZIP 50207 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 21

First frostOct 16

2012 zone5a

Was 5a 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 5b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for New Sharon, IA…

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 New Sharon, IA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 21median — 50% chance of a later frost

Safe for tender plantsMay 4only 10% chance of frost after

First fall frostOctober 16median — 10% chance by Sep 29

Growing season176 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 11 and returns around October 27.

From the NOAA station Oskaloosa, IA — 7 miles away, elevation 830 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 50207

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 10 – Mar 24

SpinachSow outdoors · Mar 10 – Mar 31

Broccoli, cabbageStart indoors · Feb 10 – Feb 24

Broccoli, cabbageTransplant · Mar 31 – Apr 14

Onion setsPlant outdoors · Mar 24 – Apr 7

PotatoesPlant outdoors · Mar 31 – Apr 14

LettuceSow outdoors · Mar 24 – Apr 7

Carrots, beetsSow outdoors · Mar 31 – Apr 14

TomatoesStart indoors · Feb 24 – Mar 10

TomatoesTransplant · Apr 28 – May 12

Peppers, eggplantStart indoors · Feb 10 – Feb 24

Peppers, eggplantTransplant · May 5 – May 19

BeansSow outdoors · Apr 28 – May 12

Sweet cornSow outdoors · Apr 28 – May 12

Cucumbers, squashSow outdoors · Apr 28 – May 12

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 21) 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 50207 came on Mar 20 — 14 days earlier than the 1991–2020 average (Apr 3).

average
Apr 32026
Mar 20

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 Iowa

473 plants native to the lower 48 states, recorded in Iowa, and rated by the USDA to survive −15 °F or colder — the bottom of zone 5b. 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 New Sharon, IA.

Soil in New Sharon, IA

The soil mapped at the center of ZIP 50207 is Otley — silty clay loam, moderately well drained.

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

pH6.0slightly acidic; most vegetables like 6.0–7.0

DrainageModerately well drainednatural drainage class

Organic matter3.5%moderate

Hydrologic groupCwater soaks in slowly

Farmland classprime farmlandUSDA classification

Map unit: Otley silty clay loam, 2 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 50207; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in New Sharon, IA

Summer high86 °Faverage high, July

Winter low12 °Faverage low, January

Hot days15days a year at 90 °F or more

Freezing nights144nights a year at 32 °F or less

Growing degree days3,296base 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)

Precipitation38.7 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: Oskaloosa, IA (7 mi away); precipitation: Oskaloosa, IA (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5b.

500275b

Barnes City, IA · 9 mi

502425b

Searsboro, IA · 9 mi

525955b

University Park, IA · 10 mi

501435b

Leighton, IA · 11 mi

525865b

Rose Hill, IA · 11 mi

525775b

Oskaloosa, IA · 11 mi

525345b

Beacon, IA · 11 mi

501715b

Montezuma, IA · 12 mi

Iowa planting zones →

Questions about 50207

What planting zone is ZIP code 50207?

ZIP code 50207 (New Sharon, IA) 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 New Sharon, IA?

The median last spring frost (32 °F) near 50207 is April 21; after May 4 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Oskaloosa station.

When is the first frost in New Sharon, IA?

The median first fall frost near 50207 is October 16, giving a median frost-free growing season of 176 days.

When should I plant tomatoes in 50207?

Start tomato seeds indoors around Feb 24 – Mar 10 and set transplants outside around Apr 28 – May 12, one to three weeks after the median last frost.

How much rain and snow does 50207 get?

About 38.7 inches of precipitation a year (NOAA 1991–2020 normals, Oskaloosa station).

How hot do summers get in New Sharon, IA?

The average high peaks at 86 °F in July, with about 15 days a year at 90 °F or more.

What kind of soil does 50207 have?

The USDA soil survey maps Otley at the center of ZIP 50207: silty clay loam, moderately well drained, pH about 6.0 (slightly acidic).

Did spring come early in New Sharon, IA in 2026?

Spring leaf-out near 50207 came on Mar 20 in 2026, 14 days earlier than the 1991–2020 average (Apr 3), according to the USA National Phenology Network Spring Index.

What kind of onions grow in New Sharon, IA?

Long-day onions: the longest day near 50207 is 15 h 11 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 50207 change?

Yes. The 2012 USDA map put 50207 in zone 5a; the 2023 map puts it in zone 5b. The newer map uses 1991–2020 data and more weather stations.