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

Planting zone for 52170 — Waterville, IA

ZIP code 52170 (Waterville, Allamakee County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 2 and the first fall frost October 11.

Where ZIP 52170 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 2
First frostOct 11
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 Waterville, 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 Waterville, IA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 2median — 50% chance of a later frost
Safe for tender plantsMay 16only 10% chance of frost after
First fall frostOctober 11median — 10% chance by Sep 28
Growing season161 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 21 and returns around October 22.

From the NOAA station Waukon, IA — 9 miles away, elevation 1,276 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 52170

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 21 – Apr 4
SpinachSow outdoors · Mar 21 – Apr 11
Broccoli, cabbageStart indoors · Feb 21 – Mar 7
Broccoli, cabbageTransplant · Apr 11 – Apr 25
Onion setsPlant outdoors · Apr 4 – Apr 18
PotatoesPlant outdoors · Apr 11 – Apr 25
LettuceSow outdoors · Apr 4 – Apr 18
Carrots, beetsSow outdoors · Apr 11 – Apr 25
TomatoesStart indoors · Mar 7 – Mar 21
TomatoesTransplant · May 9 – May 23
Peppers, eggplantStart indoors · Feb 21 – Mar 7
Peppers, eggplantTransplant · May 16 – May 30
BeansSow outdoors · May 9 – May 23
Sweet cornSow outdoors · May 9 – May 23
Cucumbers, squashSow outdoors · May 9 – May 23
Fall lettuce, spinachSow outdoors · Aug 16 – Aug 30
GarlicPlant cloves · Sep 27 – Nov 1
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 2) and first fall frost (Oct 11) 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 52170 came on Mar 30 — 14 days earlier than the 1991–2020 average (Apr 13).

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).

Soil in Waterville, IA

The soil mapped at the center of ZIP 52170 is Paintcreek — silt loam, well drained.

TextureSilt loama good balance for most vegetables
pH6.2slightly acidic; 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: Paintcreek silt loam, 18 to 30 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 52170; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Waterville, IA

Summer high81 °Faverage high, July
Winter low8 °Faverage low, January
Hot days8days a year at 90 °F or more
Freezing nights160nights a year at 32 °F or less
Growing degree days2,549base 50 °F — the season’s usable heat
Longest day15 h 23 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)
Precipitation39.2 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 24 °F, low 8 °F 24°8° JanFebruary: average high 29 °F, low 12 °F 29°12° FebMarch: average high 42 °F, low 23 °F 42°23° MarApril: average high 56 °F, low 34 °F 56°34° AprMay: average high 68 °F, low 46 °F 68°46° MayJune: average high 77 °F, low 58 °F 77°58° JunJuly: average high 81 °F, low 62 °F 81°62° JulAugust: average high 79 °F, low 59 °F 79°59° AugSeptember: average high 72 °F, low 51 °F 72°51° SepOctober: average high 59 °F, low 39 °F 59°39° OctNovember: average high 43 °F, low 27 °F 43°27° NovDecember: average high 29 °F, low 15 °F 29°15° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 1.23 in precipitation 1.2 JanFebruary: 1.25 in precipitation 1.3 FebMarch: 2.03 in precipitation 2.0 MarApril: 4.06 in precipitation 4.1 AprMay: 4.66 in precipitation 4.7 MayJune: 5.92 in precipitation 5.9 JunJuly: 4.73 in precipitation 4.7 JulAugust: 4.70 in precipitation 4.7 AugSeptember: 3.92 in precipitation 3.9 SepOctober: 2.85 in precipitation 2.9 OctNovember: 2.27 in precipitation 2.3 NovDecember: 1.57 in precipitation 1.6 Dec

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

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5a.

521465a
Harpers Ferry, IA · 6 mi
521515a
Lansing, IA · 8 mi
521725a
Waukon, IA · 9 mi
521595a
Monona, IA · 11 mi
546265a
Eastman, WI · 13 mi
521585a
Marquette, IA · 14 mi
521565a
Luana, IA · 15 mi
521575a
Mc Gregor, IA · 15 mi

Iowa planting zones →

Questions about 52170

What planting zone is ZIP code 52170?

ZIP code 52170 (Waterville, 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 Waterville, IA?

The median last spring frost (32 °F) near 52170 is May 2; after May 16 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Waukon station.

When is the first frost in Waterville, IA?

The median first fall frost near 52170 is October 11, giving a median frost-free growing season of 161 days.

When should I plant tomatoes in 52170?

Start tomato seeds indoors around Mar 7 – Mar 21 and set transplants outside around May 9 – May 23, one to three weeks after the median last frost.

How much rain and snow does 52170 get?

About 39.2 inches of precipitation a year (NOAA 1991–2020 normals, Waukon station).

How hot do summers get in Waterville, IA?

The average high peaks at 81 °F in July, with about 8 days a year at 90 °F or more.

What kind of soil does 52170 have?

The USDA soil survey maps Paintcreek at the center of ZIP 52170: silt loam, well drained, pH about 6.2 (slightly acidic).

Did spring come early in Waterville, IA in 2026?

Spring leaf-out near 52170 came on Mar 30 in 2026, 14 days earlier than the 1991–2020 average (Apr 13), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Waterville, IA?

Long-day onions: the longest day near 52170 is 15 h 23 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).