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

Planting zone for 50517 — Bancroft, IA

ZIP code 50517 (Bancroft, Kossuth County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 4 and the first fall frost October 1.

Where ZIP 50517 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 4

First frostOct 1

2012 zone5a

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 5a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Bancroft, 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 Bancroft, IA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 4median — 50% chance of a later frost

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

First fall frostOctober 1median — 10% chance by Sep 18

Growing season150 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 25 and returns around October 10.

From the NOAA station Swea City 5n, IA — 11 miles away, elevation 1,181 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 50517

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 23 – Apr 6

SpinachSow outdoors · Mar 23 – Apr 13

Broccoli, cabbageStart indoors · Feb 23 – Mar 9

Broccoli, cabbageTransplant · Apr 13 – Apr 27

Onion setsPlant outdoors · Apr 6 – Apr 20

PotatoesPlant outdoors · Apr 13 – Apr 27

LettuceSow outdoors · Apr 6 – Apr 20

Carrots, beetsSow outdoors · Apr 13 – Apr 27

TomatoesStart indoors · Mar 9 – Mar 23

TomatoesTransplant · May 11 – May 25

Peppers, eggplantStart indoors · Feb 23 – Mar 9

Peppers, eggplantTransplant · May 18 – Jun 1

BeansSow outdoors · May 11 – May 25

Sweet cornSow outdoors · May 11 – May 25

Cucumbers, squashSow outdoors · May 11 – May 25

Fall lettuce, spinachSow outdoors · Aug 6 – Aug 20

GarlicPlant cloves · Sep 17 – Oct 22

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 4) and first fall frost (Oct 1) 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 50517 came on Mar 28 — 17 days earlier than the 1991–2020 average (Apr 14).

average
Apr 142026
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 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.

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 Bancroft, IA.

Soil in Bancroft, IA

The soil mapped at the center of ZIP 50517 is Crippin — loam, somewhat poorly drained.

TextureLoama good balance for most vegetables

pH7.5slightly alkaline; most vegetables like 6.0–7.0

DrainageSomewhat poorly drainedconsider raised beds

Organic matter6%high

Hydrologic groupB/Dmoderate when drained; wet otherwise

Farmland classprime farmlandUSDA classification

Map unit: Crippin 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 50517; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Bancroft, IA

Summer high81 °Faverage high, July

Winter low5 °Faverage low, January

Hot days11days a year at 90 °F or more

Freezing nights163nights a year at 32 °F or less

Growing degree days2,421base 50 °F — the season’s usable heat

Longest day15 h 24 mindaylight on June 21

Shortest day8 h 58 mindaylight on December 21

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

Precipitation34 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: Swea City 5n, IA (11 mi away); precipitation: Burt 0.5 Nw, IA (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5a.

Armstrong, IA · 14 mi

Iowa planting zones →

Questions about 50517

What planting zone is ZIP code 50517?

ZIP code 50517 (Bancroft, 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 Bancroft, IA?

The median last spring frost (32 °F) near 50517 is May 4; after May 14 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Swea City 5n station.

When is the first frost in Bancroft, IA?

The median first fall frost near 50517 is October 1, giving a median frost-free growing season of 150 days.

When should I plant tomatoes in 50517?

Start tomato seeds indoors around Mar 9 – Mar 23 and set transplants outside around May 11 – May 25, one to three weeks after the median last frost.

How much rain and snow does 50517 get?

About 34 inches of precipitation a year (NOAA 1991–2020 normals, Burt 0.5 Nw station).

How hot do summers get in Bancroft, IA?

The average high peaks at 81 °F in July, with about 11 days a year at 90 °F or more.

What kind of soil does 50517 have?

The USDA soil survey maps Crippin at the center of ZIP 50517: loam, somewhat poorly drained, pH about 7.5 (slightly alkaline).

Did spring come early in Bancroft, IA in 2026?

Spring leaf-out near 50517 came on Mar 28 in 2026, 17 days earlier than the 1991–2020 average (Apr 14), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Bancroft, IA?

Long-day onions: the longest day near 50517 is 15 h 24 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).