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

Planting zone for 51238 — Hospers, IA

ZIP code 51238 (Hospers, Sioux County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 5 and the first fall frost September 28.

Where ZIP 51238 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.

Zone5a−20 to −15 °F
Coldest night−28.9 to −26.1 °C
Last frostMay 5
First frostSep 28
2012 zone4b

Was 4b 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 5a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Hospers, 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 Hospers, IA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 5median — 50% chance of a later frost
Safe for tender plantsMay 18only 10% chance of frost after
First fall frostSeptember 28median — 10% chance by Sep 14
Growing season145 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 28 and returns around October 6.

From the NOAA station Sheldon, IA — 7 miles away, elevation 1,421 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 51238

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 24 – Apr 7
SpinachSow outdoors · Mar 24 – Apr 14
Broccoli, cabbageStart indoors · Feb 24 – Mar 10
Broccoli, cabbageTransplant · Apr 14 – Apr 28
Onion setsPlant outdoors · Apr 7 – Apr 21
PotatoesPlant outdoors · Apr 14 – Apr 28
LettuceSow outdoors · Apr 7 – Apr 21
Carrots, beetsSow outdoors · Apr 14 – Apr 28
TomatoesStart indoors · Mar 10 – Mar 24
TomatoesTransplant · May 12 – May 26
Peppers, eggplantStart indoors · Feb 24 – Mar 10
Peppers, eggplantTransplant · May 19 – Jun 2
BeansSow outdoors · May 12 – May 26
Sweet cornSow outdoors · May 12 – May 26
Cucumbers, squashSow outdoors · May 12 – May 26
Fall lettuce, spinachSow outdoors · Aug 3 – Aug 17
GarlicPlant cloves · Sep 14 – Oct 19
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 5) and first fall frost (Sep 28) 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 51238 came on Mar 25 — 17 days earlier than the 1991–2020 average (Apr 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 5a in Iowa

461 plants native to the lower 48 states, recorded in Iowa, and rated by the USDA to survive −20 °F or colder — the bottom of zone 5a. Each links to its USDA PLANTS profile.

Trees 46

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 185

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 133

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 Hospers, IA.

Soil in Hospers, IA

The soil mapped at the center of ZIP 51238 is Primghar — silty clay loam, somewhat poorly drained.

TextureSilty clay loamholds water and nutrients; slow to drain and warm up
pH6.5neutral; most vegetables like 6.0–7.0
DrainageSomewhat poorly drainedconsider raised beds
Organic matter6.2%high
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classprime farmlandUSDA classification

Map unit: Primghar 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 51238; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Hospers, IA

Summer high83 °Faverage high, July
Winter low5 °Faverage low, January
Hot days12days a year at 90 °F or more
Freezing nights171nights a year at 32 °F or less
Growing degree days2,576base 50 °F — the season’s usable heat
Longest day15 h 22 mindaylight on June 21
Shortest day9 h 00 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation31.1 inper year, rain and melted snow
Snowfall41 inper year; 80 days with snow on the ground

Average high and low, by month

−10°0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 25 °F, low 5 °F 25°5° JanFebruary: average high 30 °F, low 9 °F 30°9° FebMarch: average high 43 °F, low 21 °F 43°21° MarApril: average high 57 °F, low 32 °F 57°32° AprMay: average high 69 °F, low 46 °F 69°46° MayJune: average high 79 °F, low 57 °F 79°57° JunJuly: average high 83 °F, low 60 °F 83°60° JulAugust: average high 80 °F, low 58 °F 80°58° AugSeptember: average high 74 °F, low 48 °F 74°48° SepOctober: average high 61 °F, low 35 °F 61°35° OctNovember: average high 44 °F, low 22 °F 44°22° NovDecember: average high 30 °F, low 11 °F 30°11° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″January: 0.88 in precipitation, 8.7 in snowfall 0.9❄9 JanFebruary: 1.00 in precipitation, 7.2 in snowfall 1.0❄7 FebMarch: 1.91 in precipitation, 6.6 in snowfall 1.9❄7 MarApril: 3.22 in precipitation, 3.3 in snowfall 3.2❄3 AprMay: 4.03 in precipitation, 0.2 in snowfall 4.0 MayJune: 4.67 in precipitation 4.7 JunJuly: 3.61 in precipitation 3.6 JulAugust: 3.26 in precipitation 3.3 AugSeptember: 3.39 in precipitation 3.4 SepOctober: 2.43 in precipitation, 0.5 in snowfall 2.4❄1 OctNovember: 1.52 in precipitation, 4.7 in snowfall 1.5❄5 NovDecember: 1.17 in precipitation, 9.6 in snowfall 1.2❄10 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Sheldon, IA (7 mi away); precipitation: Sheldon, IA (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5a.

510225a
Granville, IA · 7 mi
510035a
Alton, IA · 8 mi
512015a
Sheldon, IA · 8 mi
512315a
Archer, IA · 8 mi
510415a
Orange City, IA · 10 mi
512345a
Boyden, IA · 10 mi
512445a
Matlock, IA · 12 mi
510465a
Paullina, IA · 13 mi

Iowa planting zones →

Questions about 51238

What planting zone is ZIP code 51238?

ZIP code 51238 (Hospers, IA) is in USDA hardiness zone 5a on the 2023 map: the coldest night of an average winter reaches −20 to −15 °F (−28.9 to −26.1 °C).

When is the last frost in Hospers, IA?

The median last spring frost (32 °F) near 51238 is May 5; after May 18 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Sheldon station.

When is the first frost in Hospers, IA?

The median first fall frost near 51238 is September 28, giving a median frost-free growing season of 145 days.

When should I plant tomatoes in 51238?

Start tomato seeds indoors around Mar 10 – Mar 24 and set transplants outside around May 12 – May 26, one to three weeks after the median last frost.

How much rain and snow does 51238 get?

About 31.1 inches of precipitation a year and 41 inches of snowfall (NOAA 1991–2020 normals, Sheldon station).

How hot do summers get in Hospers, IA?

The average high peaks at 83 °F in July, with about 12 days a year at 90 °F or more.

What kind of soil does 51238 have?

The USDA soil survey maps Primghar at the center of ZIP 51238: silty clay loam, somewhat poorly drained, pH about 6.5 (neutral).

Did spring come early in Hospers, IA in 2026?

Spring leaf-out near 51238 came on Mar 25 in 2026, 17 days earlier than the 1991–2020 average (Apr 11), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Hospers, IA?

Long-day onions: the longest day near 51238 is 15 h 22 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 51238 change?

Yes. The 2012 USDA map put 51238 in zone 4b; the 2023 map puts it in zone 5a. The newer map uses 1991–2020 data and more weather stations.