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

Planting zone for 52157 — Mc Gregor, IA

ZIP code 52157 (Mc Gregor, Clayton County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is April 28 and the first fall frost October 12.

Where ZIP 52157 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 frostApr 28

First frostOct 12

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 Mc Gregor, 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 Mc Gregor, IA

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 28median — 50% chance of a later frost

Safe for tender plantsMay 11only 10% chance of frost after

First fall frostOctober 12median — 10% chance by Sep 27

Growing season166 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 16 and returns around October 22.

From the NOAA station Prairie Du Chien, WI — 6 miles away, elevation 659 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 52157

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 17 – Mar 31

SpinachSow outdoors · Mar 17 – Apr 7

Broccoli, cabbageStart indoors · Feb 17 – Mar 3

Broccoli, cabbageTransplant · Apr 7 – Apr 21

Onion setsPlant outdoors · Mar 31 – Apr 14

PotatoesPlant outdoors · Apr 7 – Apr 21

LettuceSow outdoors · Mar 31 – Apr 14

Carrots, beetsSow outdoors · Apr 7 – Apr 21

TomatoesStart indoors · Mar 3 – Mar 17

TomatoesTransplant · May 5 – May 19

Peppers, eggplantStart indoors · Feb 17 – Mar 3

Peppers, eggplantTransplant · May 12 – May 26

BeansSow outdoors · May 5 – May 19

Sweet cornSow outdoors · May 5 – May 19

Cucumbers, squashSow outdoors · May 5 – May 19

Fall lettuce, spinachSow outdoors · Aug 17 – Aug 31

GarlicPlant cloves · Sep 28 – Nov 2

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 28) and first fall frost (Oct 12) 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 52157 came on Mar 30 — 13 days earlier than the 1991–2020 average (Apr 12).

average
Apr 122026
Mar 30

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 Mc Gregor, IA.

Soil in Mc Gregor, IA

The soil mapped at the center of ZIP 52157 is Nordness — silt loam, well drained.

TextureSilt loama good balance for most vegetables

pH6.5neutral; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter2.5%moderate

Hydrologic groupDwater soaks in very slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Rock outcrop-Nordness complex, 25 to 60 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 52157; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Mc Gregor, IA

Summer high83 °Faverage high, July

Winter low10 °Faverage low, January

Hot days11days a year at 90 °F or more

Freezing nights148nights a year at 32 °F or less

Growing degree days2,900base 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)

Precipitation37.7 inper year, rain and melted snow

Snowfall34 inper year; 64 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: Prairie Du Chien, WI (6 mi away); precipitation: Prairie Du Chien, WI (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5a.

521585a

Marquette, IA · 3 mi

520475a

Farmersburg, IA · 6 mi

521595a

Monona, IA · 7 mi

538215a

Prairie Du Chien, WI · 9 mi

520495a

Garnavillo, IA · 10 mi

520725a

Saint Olaf, IA · 10 mi

538015a

Bagley, WI · 11 mi

521465a

Harpers Ferry, IA · 11 mi

Iowa planting zones →

Questions about 52157

What planting zone is ZIP code 52157?

ZIP code 52157 (Mc Gregor, 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 Mc Gregor, IA?

The median last spring frost (32 °F) near 52157 is April 28; after May 11 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Prairie Du Chien station.

When is the first frost in Mc Gregor, IA?

The median first fall frost near 52157 is October 12, giving a median frost-free growing season of 166 days.

When should I plant tomatoes in 52157?

Start tomato seeds indoors around Mar 3 – Mar 17 and set transplants outside around May 5 – May 19, one to three weeks after the median last frost.

How much rain and snow does 52157 get?

About 37.7 inches of precipitation a year and 34 inches of snowfall (NOAA 1991–2020 normals, Prairie Du Chien station).

How hot do summers get in Mc Gregor, IA?

The average high peaks at 83 °F in July, with about 11 days a year at 90 °F or more.

What kind of soil does 52157 have?

The USDA soil survey maps Nordness at the center of ZIP 52157: silt loam, well drained, pH about 6.5 (neutral).

Did spring come early in Mc Gregor, IA in 2026?

Spring leaf-out near 52157 came on Mar 30 in 2026, 13 days earlier than the 1991–2020 average (Apr 12), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Mc Gregor, IA?

Long-day onions: the longest day near 52157 is 15 h 22 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).