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

Planting zone for Shenandoah, IA

Shenandoah, IA is in USDA zone 5b across its 2 ZIP codes. The median last spring frost is April 20 and the first fall frost October 17.

Shenandoah on the zone map

Outlined: its 1 ZIP code areas · 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
ZIP codes2
Last frostApr 20
First frostOct 17
Growing season179 days

5b 2 ZIPs

Frost forecast — next 7 nights

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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 Shenandoah, IA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 20median — 50% chance of a later frost
Safe for tender plantsMay 3only 10% chance of frost after
First fall frostOctober 17median — 10% chance by Oct 1
Growing season179 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 9 and returns around October 26.

From the NOAA station Shenandoah, IA, elevation 1,001 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 Shenandoah

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 9 – Mar 23
SpinachSow outdoors · Mar 9 – Mar 30
Broccoli, cabbageStart indoors · Feb 9 – Feb 23
Broccoli, cabbageTransplant · Mar 30 – Apr 13
Onion setsPlant outdoors · Mar 23 – Apr 6
PotatoesPlant outdoors · Mar 30 – Apr 13
LettuceSow outdoors · Mar 23 – Apr 6
Carrots, beetsSow outdoors · Mar 30 – Apr 13
TomatoesStart indoors · Feb 23 – Mar 9
TomatoesTransplant · Apr 27 – May 11
Peppers, eggplantStart indoors · Feb 9 – Feb 23
Peppers, eggplantTransplant · May 4 – May 18
BeansSow outdoors · Apr 27 – May 11
Sweet cornSow outdoors · Apr 27 – May 11
Cucumbers, squashSow outdoors · Apr 27 – May 11
Fall lettuce, spinachSow outdoors · Aug 22 – Sep 5
GarlicPlant cloves · Oct 3 – Nov 7
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 20) and first fall frost (Oct 17) 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 51603 came on Mar 11 — 17 days earlier than the 1991–2020 average (Mar 28).

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.

Trees 49

American basswood100 ft · blooms late spring · low shade tolerance · to −46 °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 °Fbalsam fir60 ft · blooms mid summer · low shade tolerance · to −43 °F

Shrubs 77

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 hornbeam30 ft · blooms mid spring · low shade tolerance · to −34 °F

Wildflowers & perennials 191

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °FAmerican 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 °F

Grasses 136

arctic brome3 ft · blooms early summer · low shade tolerance · to −33 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °FBebb's sedge3 ft · blooms late spring · low shade tolerance · to −38 °FBicknell's sedge3 ft · blooms late spring · low shade tolerance · to −38 °Fbig bluestem6 ft · blooms summer · high shade tolerance · to −46 °Fblue grama1 ft · blooms early summer · high shade tolerance · to −43 °F

Vines 7

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °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 °Ftrumpet honeysuckle16 ft · blooms late summer · low shade tolerance · to −33 °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 Shenandoah, IA.

Soil in Shenandoah, IA

The soil mapped at the center of ZIP 51603 is Kennebec — silt loam, moderately well drained.

TextureSilt loama good balance for most vegetables
pH6.1slightly acidic; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter4.8%moderate
Hydrologic groupBwater soaks in moderately
Farmland classprime farmlandUSDA classification

Map unit: Kennebec silt loam, 0 to 2 percent slopes, occasionally flooded.

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 51603; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Shenandoah, IA

Summer high87 °Faverage high, July
Winter low14 °Faverage low, January
Hot days32days a year at 90 °F or more
Freezing nights137nights a year at 32 °F or less
Growing degree days3,644base 50 °F — the season’s usable heat
Longest day15 h 06 mindaylight on June 21
Shortest day9 h 15 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation36.4 inper year, rain and melted snow
Snowfall26 inper year; 43 days with snow on the ground

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 33 °F, low 14 °F 33°14° JanFebruary: average high 39 °F, low 18 °F 39°18° FebMarch: average high 52 °F, low 29 °F 52°29° MarApril: average high 64 °F, low 40 °F 64°40° AprMay: average high 74 °F, low 53 °F 74°53° MayJune: average high 83 °F, low 63 °F 83°63° JunJuly: average high 87 °F, low 67 °F 87°67° JulAugust: average high 85 °F, low 64 °F 85°64° AugSeptember: average high 79 °F, low 55 °F 79°55° SepOctober: average high 66 °F, low 42 °F 66°42° OctNovember: average high 51 °F, low 29 °F 51°29° NovDecember: average high 38 °F, low 19 °F 38°19° Dec

Precipitation by month inches · ❄ = snowfall

0″2″4″6″January: 0.92 in precipitation, 7 in snowfall 0.9❄7 JanFebruary: 1.21 in precipitation, 7.5 in snowfall 1.2❄8 FebMarch: 2.06 in precipitation, 2.8 in snowfall 2.1❄3 MarApril: 3.34 in precipitation, 1.2 in snowfall 3.3❄1 AprMay: 6.16 in precipitation 6.2 MayJune: 5.53 in precipitation 5.5 JunJuly: 4.36 in precipitation 4.4 JulAugust: 3.77 in precipitation 3.8 AugSeptember: 3.02 in precipitation 3.0 SepOctober: 2.84 in precipitation, 0.6 in snowfall 2.8❄1 OctNovember: 1.76 in precipitation, 1.5 in snowfall 1.8❄2 NovDecember: 1.40 in precipitation, 5.8 in snowfall 1.4❄6 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Shenandoah, IA (within 1 mile); precipitation: Shenandoah, IA (within 1 mile). Daylight is calculated from latitude.

ZIP codes in Shenandoah

516015b
−15 to −10 °F
516035b
−15 to −10 °F

Iowa planting zones →

Questions about Shenandoah

What planting zone is Shenandoah, IA?

Shenandoah, IA is in USDA hardiness zone 5b on the 2023 map (5b: −15 to −10 °F).

When is the last frost in Shenandoah, IA?

The median last spring frost is April 20 and the median first fall frost is October 17 (NOAA 1991–2020 normals, Shenandoah station).

When can I plant a garden in Shenandoah, IA?

Cool-season crops like peas and spinach go in around Mar 9 – Mar 30; tomatoes, peppers, beans and squash after about Apr 27, once frost risk has passed.

What kind of onions grow in Shenandoah, IA?

Long-day onions: the longest day is 15 h 06 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

How much rain and snow does Shenandoah, IA get?

About 36.4 inches of precipitation a year and 26 inches of snowfall (NOAA 1991–2020 normals).