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

Planting zone for 52040 — Dyersville, IA

ZIP code 52040 (Dyersville, Dubuque 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 10.

Where ZIP 52040 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 10
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 Dyersville, 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 Dyersville, 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 12only 10% chance of frost after
First fall frostOctober 10median — 10% chance by Sep 28
Growing season164 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 15 and returns around October 20.

From the NOAA station Cascade, IA — 16 miles away, elevation 814 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 52040

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 15 – Aug 29
GarlicPlant cloves · Sep 26 – Oct 31
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 28) and first fall frost (Oct 10) 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 52040 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).

Soil in Dyersville, IA

The soil mapped at the center of ZIP 52040 is Worthen — 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 matter4%moderate
Hydrologic groupBwater soaks in moderately
Farmland classprime farmlandUSDA classification

Map unit: Worthen silt 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 52040; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Dyersville, IA

Summer high83 °Faverage high, July
Winter low11 °Faverage low, January
Hot days11days a year at 90 °F or more
Freezing nights153nights a year at 32 °F or less
Growing degree days2,894base 50 °F — the season’s usable heat
Longest day15 h 18 mindaylight on June 21
Shortest day9 h 03 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation39.3 inper year, rain and melted snow
Snowfall31 inper year; 64 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 27 °F, low 11 °F 27°11° JanFebruary: average high 32 °F, low 15 °F 32°15° FebMarch: average high 45 °F, low 26 °F 45°26° MarApril: average high 59 °F, low 37 °F 59°37° AprMay: average high 70 °F, low 49 °F 70°49° MayJune: average high 80 °F, low 60 °F 80°60° JunJuly: average high 83 °F, low 63 °F 83°63° JulAugust: average high 81 °F, low 60 °F 81°60° AugSeptember: average high 75 °F, low 51 °F 75°51° SepOctober: average high 62 °F, low 39 °F 62°39° OctNovember: average high 46 °F, low 28 °F 46°28° NovDecember: average high 33 °F, low 18 °F 33°18° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″6″January: 1.26 in precipitation, 8.3 in snowfall 1.3❄8 JanFebruary: 1.45 in precipitation, 8.8 in snowfall 1.4❄9 FebMarch: 2.15 in precipitation, 4.2 in snowfall 2.1❄4 MarApril: 3.97 in precipitation, 0.9 in snowfall 4.0❄1 AprMay: 4.21 in precipitation 4.2 MayJune: 5.96 in precipitation 6.0 JunJuly: 4.53 in precipitation 4.5 JulAugust: 4.65 in precipitation 4.7 AugSeptember: 3.79 in precipitation 3.8 SepOctober: 3.26 in precipitation, 0.2 in snowfall 3.3 OctNovember: 2.33 in precipitation, 1.8 in snowfall 2.3❄2 NovDecember: 1.75 in precipitation, 6.9 in snowfall 1.8❄7 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Cascade, IA (16 mi away); precipitation: Cascade, IA (16 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.

520415a
Earlville, IA · 6 mi
520655a
New Vienna, IA · 6 mi
520785a
Worthington, IA · 8 mi
520565a
Luxemburg, IA · 8 mi
520465a
Farley, IA · 8 mi
520364b
Delaware, IA · 10 mi
522235a
Delhi, IA · 11 mi
520455a
Epworth, IA · 11 mi

Iowa planting zones →

Questions about 52040

What planting zone is ZIP code 52040?

ZIP code 52040 (Dyersville, 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 Dyersville, IA?

The median last spring frost (32 °F) near 52040 is April 28; after May 12 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Cascade station.

When is the first frost in Dyersville, IA?

The median first fall frost near 52040 is October 10, giving a median frost-free growing season of 164 days.

When should I plant tomatoes in 52040?

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 52040 get?

About 39.3 inches of precipitation a year and 31 inches of snowfall (NOAA 1991–2020 normals, Cascade station).

How hot do summers get in Dyersville, 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 52040 have?

The USDA soil survey maps Worthen at the center of ZIP 52040: silt loam, well drained, pH about 6.5 (neutral).

Did spring come early in Dyersville, IA in 2026?

Spring leaf-out near 52040 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 Dyersville, IA?

Long-day onions: the longest day near 52040 is 15 h 18 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).