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

Planting zone for 52778 — Wilton, IA

ZIP code 52778 (Wilton, Muscatine County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is April 18 and the first fall frost October 22.

Where ZIP 52778 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 18

First frostOct 22

2012 zone5b

Same zone as on the 2012 map. 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 Wilton, 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 Wilton, IA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 18median — 50% chance of a later frost

Safe for tender plantsMay 2only 10% chance of frost after

First fall frostOctober 22median — 10% chance by Oct 8

Growing season184 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 7 and returns around October 31.

From the NOAA station Muscatine 2n, IA — 9 miles away, elevation 679 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 52778

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 7 – Mar 21

SpinachSow outdoors · Mar 7 – Mar 28

Broccoli, cabbageStart indoors · Feb 7 – Feb 21

Broccoli, cabbageTransplant · Mar 28 – Apr 11

Onion setsPlant outdoors · Mar 21 – Apr 4

PotatoesPlant outdoors · Mar 28 – Apr 11

LettuceSow outdoors · Mar 21 – Apr 4

Carrots, beetsSow outdoors · Mar 28 – Apr 11

TomatoesStart indoors · Feb 21 – Mar 7

TomatoesTransplant · Apr 25 – May 9

Peppers, eggplantStart indoors · Feb 7 – Feb 21

Peppers, eggplantTransplant · May 2 – May 16

BeansSow outdoors · Apr 25 – May 9

Sweet cornSow outdoors · Apr 25 – May 9

Cucumbers, squashSow outdoors · Apr 25 – May 9

Fall lettuce, spinachSow outdoors · Aug 27 – Sep 10

GarlicPlant cloves · Oct 8 – Nov 12

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 18) and first fall frost (Oct 22) 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 52778 came on Mar 25 — 11 days earlier than the 1991–2020 average (Apr 5).

average
Apr 52026
Mar 25

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 Wilton, IA.

Soil in Wilton, IA

The soil mapped at the center of ZIP 52778 is Atterberry — silt loam, somewhat poorly drained.

TextureSilt loama good balance for most vegetables

pH6.4slightly acidic; most vegetables like 6.0–7.0

DrainageSomewhat poorly drainedconsider raised beds

Organic matter3.25%moderate

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classprime farmlandUSDA classification

Map unit: Atterberry silt loam, 1 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 52778; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Wilton, IA

Summer high84 °Faverage high, July

Winter low14 °Faverage low, January

Hot days18days a year at 90 °F or more

Freezing nights125nights a year at 32 °F or less

Growing degree days3,248base 50 °F — the season’s usable heat

Longest day15 h 12 mindaylight on June 21

Shortest day9 h 09 mindaylight on December 21

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

Precipitation38.3 inper year, rain and melted snow

Snowfall29 inper year; 46 days with snow on the ground

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Muscatine 2n, IA (9 mi away); precipitation: Muscatine 2n, IA (9 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

2 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

New Liberty, IA · 11 mi

527615b

Muscatine, IA · 12 mi

527725a

Tipton, IA · 12 mi

Iowa planting zones →

Questions about 52778

What planting zone is ZIP code 52778?

ZIP code 52778 (Wilton, 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 Wilton, IA?

The median last spring frost (32 °F) near 52778 is April 18; after May 2 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Muscatine 2n station.

When is the first frost in Wilton, IA?

The median first fall frost near 52778 is October 22, giving a median frost-free growing season of 184 days.

When should I plant tomatoes in 52778?

Start tomato seeds indoors around Feb 21 – Mar 7 and set transplants outside around Apr 25 – May 9, one to three weeks after the median last frost.

How much rain and snow does 52778 get?

About 38.3 inches of precipitation a year and 29 inches of snowfall (NOAA 1991–2020 normals, Muscatine 2n station).

How hot do summers get in Wilton, IA?

The average high peaks at 84 °F in July, with about 18 days a year at 90 °F or more.

What kind of soil does 52778 have?

The USDA soil survey maps Atterberry at the center of ZIP 52778: silt loam, somewhat poorly drained, pH about 6.4 (slightly acidic).

Did spring come early in Wilton, IA in 2026?

Spring leaf-out near 52778 came on Mar 25 in 2026, 11 days earlier than the 1991–2020 average (Apr 5), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Wilton, IA?

Long-day onions: the longest day near 52778 is 15 h 12 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).