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

Planting zone for 52165 — Ridgeway, IA

ZIP code 52165 (Ridgeway, Winneshiek County) is in USDA zone 4b: the coldest winter night averages −25 to −20 °F. The median last spring frost is May 8 and the first fall frost October 1.

Where ZIP 52165 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.

Zone4b−25 to −20 °F
Coldest night−31.7 to −28.9 °C
Last frostMay 8
First frostOct 1
2012 zone4b

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 4b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Ridgeway, 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 Ridgeway, IA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 8median — 50% chance of a later frost
Safe for tender plantsMay 21only 10% chance of frost after
First fall frostOctober 1median — 10% chance by Sep 19
Growing season147 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 29 and returns around October 11.

From the NOAA station Cresco 1 Ne, IA — 7 miles away, elevation 1,257 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 52165

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 27 – Apr 10
SpinachSow outdoors · Mar 27 – Apr 17
Broccoli, cabbageStart indoors · Feb 27 – Mar 13
Broccoli, cabbageTransplant · Apr 17 – May 1
Onion setsPlant outdoors · Apr 10 – Apr 24
PotatoesPlant outdoors · Apr 17 – May 1
LettuceSow outdoors · Apr 10 – Apr 24
Carrots, beetsSow outdoors · Apr 17 – May 1
TomatoesStart indoors · Mar 13 – Mar 27
TomatoesTransplant · May 15 – May 29
Peppers, eggplantStart indoors · Feb 27 – Mar 13
Peppers, eggplantTransplant · May 22 – Jun 5
BeansSow outdoors · May 15 – May 29
Sweet cornSow outdoors · May 15 – May 29
Cucumbers, squashSow outdoors · May 15 – May 29
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 8) 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 52165 came on Mar 30 — 15 days earlier than the 1991–2020 average (Apr 14).

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 4b in Iowa

426 plants native to the lower 48 states, recorded in Iowa, and rated by the USDA to survive −25 °F or colder — the bottom of zone 4b. Each links to its USDA PLANTS profile.

Trees 43

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 72

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 169

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 124

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 5

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Ftrumpet honeysuckle16 ft · blooms late summer · low shade tolerance · to −33 °FVirginia creeper1 ft · blooms late spring · medium shade tolerance · to −28 °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 Ridgeway, IA.

Soil in Ridgeway, IA

The soil mapped at the center of ZIP 52165 is Racine — loam, well drained.

TextureLoama good balance for most vegetables
pH6.8neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2.5%moderate
Hydrologic groupCwater soaks in slowly
Farmland classprime farmlandUSDA classification

Map unit: Racine 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 52165; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Ridgeway, IA

Summer high83 °Faverage high, July
Winter low6 °Faverage low, January
Hot days8days a year at 90 °F or more
Freezing nights170nights a year at 32 °F or less
Growing degree days2,568base 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)
Precipitation38 inper year, rain and melted snow
Snowfall40 inper year; 78 days with snow on the ground

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 24 °F, low 6 °F 24°6° JanFebruary: average high 29 °F, low 9 °F 29°9° FebMarch: average high 42 °F, low 21 °F 42°21° MarApril: average high 57 °F, low 33 °F 57°33° AprMay: average high 69 °F, low 45 °F 69°45° MayJune: average high 79 °F, low 56 °F 79°56° JunJuly: average high 83 °F, low 60 °F 83°60° JulAugust: average high 81 °F, low 57 °F 81°57° AugSeptember: average high 74 °F, low 48 °F 74°48° SepOctober: average high 60 °F, low 36 °F 60°36° OctNovember: average high 44 °F, low 24 °F 44°24° NovDecember: average high 30 °F, low 13 °F 30°13° Dec

Precipitation by month inches · ❄ = snowfall

0″2″4″6″January: 1.12 in precipitation, 9.4 in snowfall 1.1❄9 JanFebruary: 1.17 in precipitation, 10 in snowfall 1.2❄10 FebMarch: 1.89 in precipitation, 6 in snowfall 1.9❄6 MarApril: 3.74 in precipitation, 2.4 in snowfall 3.7❄2 AprMay: 4.47 in precipitation, 0.2 in snowfall 4.5 MayJune: 6.26 in precipitation 6.3 JunJuly: 4.83 in precipitation 4.8 JulAugust: 4.59 in precipitation 4.6 AugSeptember: 3.76 in precipitation 3.8 SepOctober: 2.87 in precipitation, 0.2 in snowfall 2.9 OctNovember: 1.88 in precipitation, 2.6 in snowfall 1.9❄3 NovDecember: 1.42 in precipitation, 9.5 in snowfall 1.4❄10 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Cresco 1 Ne, IA (7 mi away); precipitation: Cresco 1 Ne, IA (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

521364b
Cresco, IA · 7 mi
521325a
Calmar, IA · 8 mi
521684b
Spillville, IA · 8 mi
521634b
Protivin, IA · 8 mi
521445a
Fort Atkinson, IA · 12 mi
521015a
Decorah, IA · 12 mi
521545a
Lawler, IA · 16 mi
521715a
Waucoma, IA · 17 mi

Iowa planting zones →

Questions about 52165

What planting zone is ZIP code 52165?

ZIP code 52165 (Ridgeway, IA) is in USDA hardiness zone 4b on the 2023 map: the coldest night of an average winter reaches −25 to −20 °F (−31.7 to −28.9 °C).

When is the last frost in Ridgeway, IA?

The median last spring frost (32 °F) near 52165 is May 8; after May 21 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Cresco 1 Ne station.

When is the first frost in Ridgeway, IA?

The median first fall frost near 52165 is October 1, giving a median frost-free growing season of 147 days.

When should I plant tomatoes in 52165?

Start tomato seeds indoors around Mar 13 – Mar 27 and set transplants outside around May 15 – May 29, one to three weeks after the median last frost.

How much rain and snow does 52165 get?

About 38 inches of precipitation a year and 40 inches of snowfall (NOAA 1991–2020 normals, Cresco 1 Ne station).

How hot do summers get in Ridgeway, IA?

The average high peaks at 83 °F in July, with about 8 days a year at 90 °F or more.

What kind of soil does 52165 have?

The USDA soil survey maps Racine at the center of ZIP 52165: loam, well drained, pH about 6.8 (neutral).

Did spring come early in Ridgeway, IA in 2026?

Spring leaf-out near 52165 came on Mar 30 in 2026, 15 days earlier than the 1991–2020 average (Apr 14), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Ridgeway, IA?

Long-day onions: the longest day near 52165 is 15 h 24 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).