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

Planting zone for 61041 — Hanover, IL

ZIP code 61041 (Hanover, Jo Daviess County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 1 and the first fall frost October 9.

Where ZIP 61041 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 1

First frostOct 9

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 Hanover, IL…

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 Hanover, IL

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 1median — 50% chance of a later frost

Safe for tender plantsMay 17only 10% chance of frost after

First fall frostOctober 9median — 10% chance by Sep 25

Growing season160 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 20 and returns around October 19.

From the NOAA station Elizabeth, IL — 5 miles away, elevation 676 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 61041

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 20 – Apr 3

SpinachSow outdoors · Mar 20 – Apr 10

Broccoli, cabbageStart indoors · Feb 20 – Mar 6

Broccoli, cabbageTransplant · Apr 10 – Apr 24

Onion setsPlant outdoors · Apr 3 – Apr 17

PotatoesPlant outdoors · Apr 10 – Apr 24

LettuceSow outdoors · Apr 3 – Apr 17

Carrots, beetsSow outdoors · Apr 10 – Apr 24

TomatoesStart indoors · Mar 6 – Mar 20

TomatoesTransplant · May 8 – May 22

Peppers, eggplantStart indoors · Feb 20 – Mar 6

Peppers, eggplantTransplant · May 15 – May 29

BeansSow outdoors · May 8 – May 22

Sweet cornSow outdoors · May 8 – May 22

Cucumbers, squashSow outdoors · May 8 – May 22

Fall lettuce, spinachSow outdoors · Aug 14 – Aug 28

GarlicPlant cloves · Sep 25 – Oct 30

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 1) and first fall frost (Oct 9) 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 61041 came on Mar 28 — 12 days earlier than the 1991–2020 average (Apr 9).

average
Apr 92026
Mar 28

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 Illinois

550 plants native to the lower 48 states, recorded in Illinois, 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 Hanover, IL.

Soil in Hanover, IL

The soil mapped at the center of ZIP 61041 is Rozetta — 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 matter1.5%low — add compost

Hydrologic groupBwater soaks in moderately

Farmland classFarmland of statewide importanceUSDA classification

Map unit: Rozetta silt loam, 5 to 10 percent slopes, eroded.

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 61041; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Hanover, IL

Summer high83 °Faverage high, July

Winter low10 °Faverage low, January

Hot days11days a year at 90 °F or more

Freezing nights156nights a year at 32 °F or less

Growing degree days2,781base 50 °F — the season’s usable heat

Longest day15 h 16 mindaylight on June 21

Shortest day9 h 05 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation39.4 inper year, rain and melted snow

Snowfall30 inper year; 56 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: Elizabeth, IL (5 mi away); precipitation: Elizabeth, IL (5 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5a.

Springbrook, IA · 11 mi

520645a

Miles, IA · 12 mi

520715a

Saint Donatus, IA · 13 mi

610755a

Scales Mound, IL · 13 mi

520745a

Spragueville, IA · 14 mi

Illinois planting zones →

Questions about 61041

What planting zone is ZIP code 61041?

ZIP code 61041 (Hanover, IL) 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 Hanover, IL?

The median last spring frost (32 °F) near 61041 is May 1; after May 17 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Elizabeth station.

When is the first frost in Hanover, IL?

The median first fall frost near 61041 is October 9, giving a median frost-free growing season of 160 days.

When should I plant tomatoes in 61041?

Start tomato seeds indoors around Mar 6 – Mar 20 and set transplants outside around May 8 – May 22, one to three weeks after the median last frost.

How much rain and snow does 61041 get?

About 39.4 inches of precipitation a year and 30 inches of snowfall (NOAA 1991–2020 normals, Elizabeth station).

How hot do summers get in Hanover, IL?

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 61041 have?

The USDA soil survey maps Rozetta at the center of ZIP 61041: silt loam, well drained, pH about 6.2 (slightly acidic).

Did spring come early in Hanover, IL in 2026?

Spring leaf-out near 61041 came on Mar 28 in 2026, 12 days earlier than the 1991–2020 average (Apr 9), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Hanover, IL?

Long-day onions: the longest day near 61041 is 15 h 16 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).