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

Planting zone for 52330 — Ryan, IA

ZIP code 52330 (Ryan, Delaware County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 3 and the first fall frost October 7.

Where ZIP 52330 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 3
First frostOct 7
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 Ryan, 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 Ryan, IA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 3median — 50% chance of a later frost
Safe for tender plantsMay 17only 10% chance of frost after
First fall frostOctober 7median — 10% chance by Sep 22
Growing season156 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 22 and returns around October 18.

From the NOAA station Coggon, IA — 5 miles away, elevation 902 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 52330

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 22 – Apr 5
SpinachSow outdoors · Mar 22 – Apr 12
Broccoli, cabbageStart indoors · Feb 22 – Mar 8
Broccoli, cabbageTransplant · Apr 12 – Apr 26
Onion setsPlant outdoors · Apr 5 – Apr 19
PotatoesPlant outdoors · Apr 12 – Apr 26
LettuceSow outdoors · Apr 5 – Apr 19
Carrots, beetsSow outdoors · Apr 12 – Apr 26
TomatoesStart indoors · Mar 8 – Mar 22
TomatoesTransplant · May 10 – May 24
Peppers, eggplantStart indoors · Feb 22 – Mar 8
Peppers, eggplantTransplant · May 17 – May 31
BeansSow outdoors · May 10 – May 24
Sweet cornSow outdoors · May 10 – May 24
Cucumbers, squashSow outdoors · May 10 – May 24
Fall lettuce, spinachSow outdoors · Aug 12 – Aug 26
GarlicPlant cloves · Sep 23 – Oct 28
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 3) and first fall frost (Oct 7) 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 52330 came on Mar 25 — 18 days earlier than the 1991–2020 average (Apr 12).

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 Ryan, IA.

Soil in Ryan, IA

The soil mapped at the center of ZIP 52330 is Kenyon — loam, moderately well drained.

TextureLoama good balance for most vegetables
pH5.8moderately acidic; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter2.9%moderate
Hydrologic groupCwater soaks in slowly
Farmland classprime farmlandUSDA classification

Map unit: Kenyon 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 52330; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Ryan, IA

Summer high83 °Faverage high, July
Winter low9 °Faverage low, January
Hot days11days a year at 90 °F or more
Freezing nights160nights a year at 32 °F or less
Growing degree days2,670base 50 °F — the season’s usable heat
Longest day15 h 17 mindaylight on June 21
Shortest day9 h 04 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation39.1 inper year, rain and melted snow

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 26 °F, low 9 °F 26°9° JanFebruary: average high 31 °F, low 13 °F 31°13° FebMarch: average high 44 °F, low 24 °F 44°24° MarApril: average high 58 °F, low 34 °F 58°34° AprMay: average high 70 °F, low 46 °F 70°46° MayJune: average high 80 °F, low 57 °F 80°57° JunJuly: average high 83 °F, low 61 °F 83°61° JulAugust: average high 81 °F, low 58 °F 81°58° AugSeptember: average high 75 °F, low 49 °F 75°49° SepOctober: average high 61 °F, low 37 °F 61°37° OctNovember: average high 45 °F, low 26 °F 45°26° NovDecember: average high 32 °F, low 16 °F 32°16° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 1.22 in precipitation 1.2 JanFebruary: 1.29 in precipitation 1.3 FebMarch: 2.03 in precipitation 2.0 MarApril: 3.91 in precipitation 3.9 AprMay: 4.78 in precipitation 4.8 MayJune: 5.87 in precipitation 5.9 JunJuly: 4.96 in precipitation 5.0 JulAugust: 4.29 in precipitation 4.3 AugSeptember: 3.94 in precipitation 3.9 SepOctober: 3.08 in precipitation 3.1 OctNovember: 2.22 in precipitation 2.2 NovDecember: 1.56 in precipitation 1.6 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Coggon, IA (5 mi away); precipitation: Coggon, IA (5 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

522185a
Coggon, IA · 4 mi
506545a
Masonville, IA · 5 mi
522195a
Prairieburg, IA · 9 mi
520575a
Manchester, IA · 10 mi
522235a
Delhi, IA · 10 mi
523445a
Troy Mills, IA · 10 mi
522145a
Central City, IA · 11 mi
520364b
Delaware, IA · 12 mi

Iowa planting zones →

Questions about 52330

What planting zone is ZIP code 52330?

ZIP code 52330 (Ryan, 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 Ryan, IA?

The median last spring frost (32 °F) near 52330 is May 3; after May 17 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Coggon station.

When is the first frost in Ryan, IA?

The median first fall frost near 52330 is October 7, giving a median frost-free growing season of 156 days.

When should I plant tomatoes in 52330?

Start tomato seeds indoors around Mar 8 – Mar 22 and set transplants outside around May 10 – May 24, one to three weeks after the median last frost.

How much rain and snow does 52330 get?

About 39.1 inches of precipitation a year (NOAA 1991–2020 normals, Coggon station).

How hot do summers get in Ryan, 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 52330 have?

The USDA soil survey maps Kenyon at the center of ZIP 52330: loam, moderately well drained, pH about 5.8 (moderately acidic).

Did spring come early in Ryan, IA in 2026?

Spring leaf-out near 52330 came on Mar 25 in 2026, 18 days earlier than the 1991–2020 average (Apr 12), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Ryan, IA?

Long-day onions: the longest day near 52330 is 15 h 17 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).