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

Planting zone for 61731 — Cropsey, IL

ZIP code 61731 (Cropsey, McLean County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is April 21 and the first fall frost October 17.

Where ZIP 61731 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.

Zone6a−10 to −5 °F
Coldest night−23.3 to −20.6 °C
Last frostApr 21
First frostOct 17
2012 zone5b

Was 5b on the 2012 map — half a zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Cropsey, 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 Cropsey, IL

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 21median — 50% chance of a later frost
Safe for tender plantsMay 5only 10% chance of frost after
First fall frostOctober 17median — 10% chance by Oct 5
Growing season178 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 11 and returns around October 28.

From the NOAA station Gibson City, IL — 11 miles away, elevation 751 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 61731

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 10 – Mar 24
SpinachSow outdoors · Mar 10 – Mar 31
Broccoli, cabbageStart indoors · Feb 10 – Feb 24
Broccoli, cabbageTransplant · Mar 31 – Apr 14
Onion setsPlant outdoors · Mar 24 – Apr 7
PotatoesPlant outdoors · Mar 31 – Apr 14
LettuceSow outdoors · Mar 24 – Apr 7
Carrots, beetsSow outdoors · Mar 31 – Apr 14
TomatoesStart indoors · Feb 24 – Mar 10
TomatoesTransplant · Apr 28 – May 12
Peppers, eggplantStart indoors · Feb 10 – Feb 24
Peppers, eggplantTransplant · May 5 – May 19
BeansSow outdoors · Apr 28 – May 12
Sweet cornSow outdoors · Apr 28 – May 12
Cucumbers, squashSow outdoors · Apr 28 – May 12
Fall lettuce, spinachSow outdoors · Aug 22 – Sep 5
GarlicPlant cloves · Oct 3 – Nov 7
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 21) and first fall frost (Oct 17) 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 61731 came on Mar 12 — 20 days earlier than the 1991–2020 average (Apr 1).

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 6a in Illinois

610 plants native to the lower 48 states, recorded in Illinois, and rated by the USDA to survive −10 °F or colder — the bottom of zone 6a. Each links to its USDA PLANTS profile.

Trees 78

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 108

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 220

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 178

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 9

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °Fcatbird grape30 ft · blooms late spring · medium shade tolerance · to −13 °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 °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 Cropsey, IL.

Soil in Cropsey, IL

The soil mapped at the center of ZIP 61731 is Drummer — silty clay loam, poorly drained.

TextureSilty clay loamholds water and nutrients; slow to drain and warm up
pH6.7neutral; most vegetables like 6.0–7.0
DrainagePoorly drainedconsider raised beds
Organic matter5.5%high
Hydrologic groupB/Dmoderate when drained; wet otherwise
Farmland classPrime farmland if drainedUSDA classification

Map unit: Drummer and Elpaso silty clay loams, 0 to 2 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 61731; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Cropsey, IL

Summer high84 °Faverage high, July
Winter low16 °Faverage low, January
Hot days19days a year at 90 °F or more
Freezing nights130nights a year at 32 °F or less
Growing degree days3,262base 50 °F — the season’s usable heat
Longest day15 h 05 mindaylight on June 21
Shortest day9 h 16 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation35.5 inper year, rain and melted snow
Snowfall14 inper year; 21 days with snow on the ground

Average high and low, by month

10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 32 °F, low 16 °F 32°16° JanFebruary: average high 37 °F, low 20 °F 37°20° FebMarch: average high 48 °F, low 29 °F 48°29° MarApril: average high 62 °F, low 39 °F 62°39° AprMay: average high 73 °F, low 51 °F 73°51° MayJune: average high 82 °F, low 61 °F 82°61° JunJuly: average high 84 °F, low 64 °F 84°64° JulAugust: average high 83 °F, low 62 °F 83°62° AugSeptember: average high 78 °F, low 53 °F 78°53° SepOctober: average high 64 °F, low 41 °F 64°41° OctNovember: average high 49 °F, low 31 °F 49°31° NovDecember: average high 37 °F, low 22 °F 37°22° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″January: 1.91 in precipitation, 3.7 in snowfall 1.9❄4 JanFebruary: 1.60 in precipitation, 5.1 in snowfall 1.6❄5 FebMarch: 2.21 in precipitation, 1.4 in snowfall 2.2❄1 MarApril: 3.28 in precipitation, 0.1 in snowfall 3.3 AprMay: 4.15 in precipitation 4.2 MayJune: 4.18 in precipitation 4.2 JunJuly: 4.14 in precipitation 4.1 JulAugust: 3.41 in precipitation 3.4 AugSeptember: 3.07 in precipitation 3.1 SepOctober: 3.14 in precipitation 3.1 OctNovember: 2.47 in precipitation, 0.4 in snowfall 2.5 NovDecember: 1.93 in precipitation, 3.3 in snowfall 1.9❄3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Gibson City, IL (11 mi away); precipitation: Fairbury Wwtp, IL (9 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

617206a
Anchor, IL · 4 mi
617756a
Strawn, IL · 6 mi
617736a
Sibley, IL · 7 mi
617286a
Colfax, IL · 8 mi
617396a
Fairbury, IL · 8 mi
617416a
Forrest, IL · 11 mi
609366a
Gibson City, IL · 12 mi
617706a
Saybrook, IL · 12 mi

Illinois planting zones →

Questions about 61731

What planting zone is ZIP code 61731?

ZIP code 61731 (Cropsey, IL) is in USDA hardiness zone 6a on the 2023 map: the coldest night of an average winter reaches −10 to −5 °F (−23.3 to −20.6 °C).

When is the last frost in Cropsey, IL?

The median last spring frost (32 °F) near 61731 is April 21; after May 5 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Gibson City station.

When is the first frost in Cropsey, IL?

The median first fall frost near 61731 is October 17, giving a median frost-free growing season of 178 days.

When should I plant tomatoes in 61731?

Start tomato seeds indoors around Feb 24 – Mar 10 and set transplants outside around Apr 28 – May 12, one to three weeks after the median last frost.

How much rain and snow does 61731 get?

About 35.5 inches of precipitation a year and 14 inches of snowfall (NOAA 1991–2020 normals, Fairbury Wwtp station).

How hot do summers get in Cropsey, IL?

The average high peaks at 84 °F in July, with about 19 days a year at 90 °F or more.

What kind of soil does 61731 have?

The USDA soil survey maps Drummer at the center of ZIP 61731: silty clay loam, poorly drained, pH about 6.7 (neutral).

Did spring come early in Cropsey, IL in 2026?

Spring leaf-out near 61731 came on Mar 12 in 2026, 20 days earlier than the 1991–2020 average (Apr 1), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Cropsey, IL?

Long-day onions: the longest day near 61731 is 15 h 05 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 61731 change?

Yes. The 2012 USDA map put 61731 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.