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

Planting zone for 61442 — Keithsburg, IL

ZIP code 61442 (Keithsburg, Mercer County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is April 14 and the first fall frost October 24.

Where ZIP 61442 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.

Zone5b−15 to −10 °F
Coldest night−26.1 to −23.3 °C
Last frostApr 14
First frostOct 24
2012 zone5b

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 5b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Keithsburg, 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 Keithsburg, IL

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 14median — 50% chance of a later frost
Safe for tender plantsMay 2only 10% chance of frost after
First fall frostOctober 24median — 10% chance by Oct 9
Growing season190 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 5 and returns around November 1.

From the NOAA station New Boston Dam 17, IL — 9 miles away, elevation 548 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 61442

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 3 – Mar 17
SpinachSow outdoors · Mar 3 – Mar 24
Broccoli, cabbageStart indoors · Feb 3 – Feb 17
Broccoli, cabbageTransplant · Mar 24 – Apr 7
Onion setsPlant outdoors · Mar 17 – Mar 31
PotatoesPlant outdoors · Mar 24 – Apr 7
LettuceSow outdoors · Mar 17 – Mar 31
Carrots, beetsSow outdoors · Mar 24 – Apr 7
TomatoesStart indoors · Feb 17 – Mar 3
TomatoesTransplant · Apr 21 – May 5
Peppers, eggplantStart indoors · Feb 3 – Feb 17
Peppers, eggplantTransplant · Apr 28 – May 12
BeansSow outdoors · Apr 21 – May 5
Sweet cornSow outdoors · Apr 21 – May 5
Cucumbers, squashSow outdoors · Apr 21 – May 5
Fall lettuce, spinachSow outdoors · Aug 29 – Sep 12
GarlicPlant cloves · Oct 10 – Nov 14
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 14) and first fall frost (Oct 24) 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 61442 came on Mar 15 — 18 days earlier than the 1991–2020 average (Apr 2).

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 5b in Illinois

584 plants native to the lower 48 states, recorded in Illinois, and rated by the USDA to survive −15 °F or colder — the bottom of zone 5b. Each links to its USDA PLANTS profile.

Trees 77

American basswood100 ft · blooms late spring · low shade tolerance · to −46 °FAmerican beech80 ft · blooms mid spring · low shade tolerance · to −44 °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 °F

Shrubs 102

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 holly40 ft · blooms mid spring · low shade tolerance · to −20 °F

Wildflowers & perennials 210

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 173

American beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °Farctic brome3 ft · blooms early summer · low shade tolerance · to −33 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °FBailey's sedge2.1 ft · blooms late spring · low shade tolerance · to −33 °Fbeaked sedge4 ft · blooms late spring · low shade tolerance · to −38 °Fbeaked spikerush3 ft · blooms late spring · high shade tolerance · to −28 °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 Keithsburg, IL.

Soil in Keithsburg, IL

The soil mapped at the center of ZIP 61442 is Ade — loamy fine sand, somewhat excessively drained.

TextureLoamy fine sanddrains and warms fast; dries out and needs more feeding
pH5.8moderately acidic; most vegetables like 6.0–7.0
DrainageSomewhat excessively drainednatural drainage class
Organic matter1.5%low — add compost
Hydrologic groupAwater soaks in fast
Farmland classNot prime farmlandUSDA classification

Map unit: Ade loamy fine sand, 2 to 7 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 61442; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Keithsburg, IL

Summer high86 °Faverage high, July
Winter low15 °Faverage low, January
Hot days24days a year at 90 °F or more
Freezing nights122nights a year at 32 °F or less
Growing degree days3,439base 50 °F — the season’s usable heat
Longest day15 h 08 mindaylight on June 21
Shortest day9 h 13 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation37.3 inper year, rain and melted snow
Snowfall20 inper year

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 32 °F, low 15 °F 32°15° JanFebruary: average high 36 °F, low 19 °F 36°19° FebMarch: average high 49 °F, low 30 °F 49°30° MarApril: average high 62 °F, low 40 °F 62°40° AprMay: average high 73 °F, low 52 °F 73°52° MayJune: average high 83 °F, low 62 °F 83°62° JunJuly: average high 86 °F, low 65 °F 86°65° JulAugust: average high 84 °F, low 63 °F 84°63° AugSeptember: average high 77 °F, low 55 °F 77°55° SepOctober: average high 64 °F, low 43 °F 64°43° OctNovember: average high 49 °F, low 32 °F 49°32° NovDecember: average high 37 °F, low 22 °F 37°22° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″January: 1.55 in precipitation, 6.8 in snowfall 1.6❄7 JanFebruary: 1.91 in precipitation, 3.9 in snowfall 1.9❄4 FebMarch: 2.43 in precipitation, 3.4 in snowfall 2.4❄3 MarApril: 3.83 in precipitation, 0.6 in snowfall 3.8❄1 AprMay: 4.82 in precipitation 4.8 MayJune: 4.80 in precipitation 4.8 JunJuly: 3.49 in precipitation 3.5 JulAugust: 3.53 in precipitation 3.5 AugSeptember: 3.83 in precipitation 3.8 SepOctober: 2.80 in precipitation 2.8 OctNovember: 2.24 in precipitation, 0.5 in snowfall 2.2❄1 NovDecember: 2.04 in precipitation, 5.2 in snowfall 2.0❄5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: New Boston Dam 17, IL (9 mi away); precipitation: Keithsburg, IL (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5b.

614765b
Seaton, IL · 5 mi
526465b
Oakville, IA · 5 mi
612605b
Joy, IL · 9 mi
614695b
Oquawka, IL · 10 mi
614535b
Little York, IL · 10 mi
612725b
New Boston, IL · 11 mi
526535b
Wapello, IA · 13 mi
526375b
Mediapolis, IA · 13 mi

Illinois planting zones →

Questions about 61442

What planting zone is ZIP code 61442?

ZIP code 61442 (Keithsburg, IL) is in USDA hardiness zone 5b on the 2023 map: the coldest night of an average winter reaches −15 to −10 °F (−26.1 to −23.3 °C).

When is the last frost in Keithsburg, IL?

The median last spring frost (32 °F) near 61442 is April 14; after May 2 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, New Boston Dam 17 station.

When is the first frost in Keithsburg, IL?

The median first fall frost near 61442 is October 24, giving a median frost-free growing season of 190 days.

When should I plant tomatoes in 61442?

Start tomato seeds indoors around Feb 17 – Mar 3 and set transplants outside around Apr 21 – May 5, one to three weeks after the median last frost.

How much rain and snow does 61442 get?

About 37.3 inches of precipitation a year and 20 inches of snowfall (NOAA 1991–2020 normals, Keithsburg station).

How hot do summers get in Keithsburg, IL?

The average high peaks at 86 °F in July, with about 24 days a year at 90 °F or more.

What kind of soil does 61442 have?

The USDA soil survey maps Ade at the center of ZIP 61442: loamy fine sand, somewhat excessively drained, pH about 5.8 (moderately acidic).

Did spring come early in Keithsburg, IL in 2026?

Spring leaf-out near 61442 came on Mar 15 in 2026, 18 days earlier than the 1991–2020 average (Apr 2), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Keithsburg, IL?

Long-day onions: the longest day near 61442 is 15 h 08 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).