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

Planting zone for 61866 — Rantoul, IL

ZIP code 61866 (Rantoul, Champaign 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 18.

Where ZIP 61866 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 18
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 Rantoul, 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 Rantoul, 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 6only 10% chance of frost after
First fall frostOctober 18median — 10% chance by Oct 5
Growing season179 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 10 and returns around October 29.

From the NOAA station Rantoul, IL — within 1 mile, elevation 742 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 61866

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 23 – Sep 6
GarlicPlant cloves · Oct 4 – Nov 8
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 21) and first fall frost (Oct 18) 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 61866 came on Mar 12 — 18 days earlier than the 1991–2020 average (Mar 30).

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 Rantoul, IL.

Soil in Rantoul, IL

The soil mapped at the center of ZIP 61866 is Orthents — silty clay, moderately well drained. Much of the area is built over (urban land); this is the natural soil underneath.

TextureSilty clayholds water and nutrients; slow to drain and warm up
pH6.7neutral; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter1.25%low — add compost
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Urban land.

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 61866; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Rantoul, IL

Summer high88 °Faverage high, July
Winter low16 °Faverage low, January
Hot days34days a year at 90 °F or more
Freezing nights131nights a year at 32 °F or less
Growing degree days3,623base 50 °F — the season’s usable heat
Longest day15 h 03 mindaylight on June 21
Shortest day9 h 18 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation40.4 inper year, rain and melted snow

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 34 °F, low 16 °F 34°16° JanFebruary: average high 40 °F, low 20 °F 40°20° FebMarch: average high 51 °F, low 29 °F 51°29° MarApril: average high 64 °F, low 40 °F 64°40° AprMay: average high 75 °F, low 51 °F 75°51° MayJune: average high 85 °F, low 62 °F 85°62° JunJuly: average high 88 °F, low 64 °F 88°64° JulAugust: average high 86 °F, low 62 °F 86°62° AugSeptember: average high 81 °F, low 54 °F 81°54° SepOctober: average high 67 °F, low 42 °F 67°42° OctNovember: average high 52 °F, low 31 °F 52°31° NovDecember: average high 40 °F, low 22 °F 40°22° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 2.54 in precipitation 2.5 JanFebruary: 2.01 in precipitation 2.0 FebMarch: 2.58 in precipitation 2.6 MarApril: 3.98 in precipitation 4.0 AprMay: 4.33 in precipitation 4.3 MayJune: 4.61 in precipitation 4.6 JunJuly: 4.44 in precipitation 4.4 JulAugust: 3.86 in precipitation 3.9 AugSeptember: 3.28 in precipitation 3.3 SepOctober: 3.32 in precipitation 3.3 OctNovember: 3.19 in precipitation 3.2 NovDecember: 2.21 in precipitation 2.2 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Rantoul, IL (within 1 mile); precipitation: Rantoul, IL (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

618786a
Thomasboro, IL · 5 mi
609496a
Ludlow, IL · 5 mi
618406a
Dewey, IL · 8 mi
618476a
Gifford, IL · 8 mi
609576a
Paxton, IL · 9 mi
618626a
Penfield, IL · 11 mi
618436a
Fisher, IL · 11 mi
609336a
Elliott, IL · 12 mi

Illinois planting zones →

Questions about 61866

What planting zone is ZIP code 61866?

ZIP code 61866 (Rantoul, 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 Rantoul, IL?

The median last spring frost (32 °F) near 61866 is April 21; after May 6 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Rantoul station.

When is the first frost in Rantoul, IL?

The median first fall frost near 61866 is October 18, giving a median frost-free growing season of 179 days.

When should I plant tomatoes in 61866?

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 61866 get?

About 40.4 inches of precipitation a year (NOAA 1991–2020 normals, Rantoul station).

How hot do summers get in Rantoul, IL?

The average high peaks at 88 °F in July, with about 34 days a year at 90 °F or more.

What kind of soil does 61866 have?

The USDA soil survey maps Orthents at the center of ZIP 61866: silty clay, moderately well drained, pH about 6.7 (neutral).

Did spring come early in Rantoul, IL in 2026?

Spring leaf-out near 61866 came on Mar 12 in 2026, 18 days earlier than the 1991–2020 average (Mar 30), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Rantoul, IL?

Long-day onions: the longest day near 61866 is 15 h 03 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 61866 change?

Yes. The 2012 USDA map put 61866 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.