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

Planting zone for Pekin, IL

Pekin, IL is in USDA zone 6a across its 3 ZIP codes. The median last spring frost is April 16 and the first fall frost October 23.

Pekin on the zone map

Outlined: its 1 ZIP code areas · 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
ZIP codes3
Last frostApr 16
First frostOct 23
Growing season189 days

6a 3 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

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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 Pekin, IL

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 16median — 50% chance of a later frost
Safe for tender plantsMay 4only 10% chance of frost after
First fall frostOctober 23median — 10% chance by Oct 9
Growing season189 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 5 and returns around November 2.

From the NOAA station Peoria Gtr Peoria Airport, IL, elevation 650 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 Pekin

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 5 – Mar 19
SpinachSow outdoors · Mar 5 – Mar 26
Broccoli, cabbageStart indoors · Feb 5 – Feb 19
Broccoli, cabbageTransplant · Mar 26 – Apr 9
Onion setsPlant outdoors · Mar 19 – Apr 2
PotatoesPlant outdoors · Mar 26 – Apr 9
LettuceSow outdoors · Mar 19 – Apr 2
Carrots, beetsSow outdoors · Mar 26 – Apr 9
TomatoesStart indoors · Feb 19 – Mar 5
TomatoesTransplant · Apr 23 – May 7
Peppers, eggplantStart indoors · Feb 5 – Feb 19
Peppers, eggplantTransplant · Apr 30 – May 14
BeansSow outdoors · Apr 23 – May 7
Sweet cornSow outdoors · Apr 23 – May 7
Cucumbers, squashSow outdoors · Apr 23 – May 7
Fall lettuce, spinachSow outdoors · Aug 28 – Sep 11
GarlicPlant cloves · Oct 9 – Nov 13
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 16) and first fall frost (Oct 23) 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 61555 came on Mar 11 — 17 days earlier than the 1991–2020 average (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 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 Pekin, IL.

Soil in Pekin, IL

The soil mapped at the center of ZIP 61555 is Disco — sandy loam, well drained.

TextureSandy loamdrains and warms fast; dries out and needs more feeding
pH5.8moderately acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2.5%moderate
Hydrologic groupAwater soaks in fast
Farmland classprime farmlandUSDA classification

Map unit: Disco sandy 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 61555; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Pekin, IL

Summer high86 °Faverage high, July
Winter low18 °Faverage low, January
Hot days23days a year at 90 °F or more
Freezing nights118nights a year at 32 °F or less
Growing degree days3,670base 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)
Precipitation39.5 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 18 °F 34°18° JanFebruary: average high 39 °F, low 21 °F 39°21° FebMarch: average high 51 °F, low 32 °F 51°32° MarApril: average high 64 °F, low 42 °F 64°42° AprMay: average high 74 °F, low 53 °F 74°53° MayJune: average high 83 °F, low 62 °F 83°62° JunJuly: average high 86 °F, low 66 °F 86°66° JulAugust: average high 85 °F, low 64 °F 85°64° AugSeptember: average high 78 °F, low 56 °F 78°56° SepOctober: average high 65 °F, low 44 °F 65°44° OctNovember: average high 51 °F, low 33 °F 51°33° NovDecember: average high 39 °F, low 23 °F 39°23° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 1.94 in precipitation 1.9 JanFebruary: 1.89 in precipitation 1.9 FebMarch: 2.70 in precipitation 2.7 MarApril: 4.09 in precipitation 4.1 AprMay: 4.62 in precipitation 4.6 MayJune: 4.08 in precipitation 4.1 JunJuly: 4.34 in precipitation 4.3 JulAugust: 4.29 in precipitation 4.3 AugSeptember: 3.29 in precipitation 3.3 SepOctober: 3.21 in precipitation 3.2 OctNovember: 2.88 in precipitation 2.9 NovDecember: 2.14 in precipitation 2.1 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Peoria Gtr Peoria Airport, IL (7 mi away); precipitation: Pekin 3.6 Sse, IL (4 mi away). Daylight is calculated from latitude.

ZIP codes in Pekin

615546a
−10 to −5 °F
615556a
−10 to −5 °F
615586a
−10 to −5 °F

Illinois planting zones →

Questions about Pekin

What planting zone is Pekin, IL?

Pekin, IL is in USDA hardiness zone 6a on the 2023 map (6a: −10 to −5 °F).

When is the last frost in Pekin, IL?

The median last spring frost is April 16 and the median first fall frost is October 23 (NOAA 1991–2020 normals, Peoria Gtr Peoria Airport station).

When can I plant a garden in Pekin, IL?

Cool-season crops like peas and spinach go in around Mar 5 – Mar 26; tomatoes, peppers, beans and squash after about Apr 23, once frost risk has passed.

What kind of onions grow in Pekin, IL?

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

How much rain and snow does Pekin, IL get?

About 39.5 inches of precipitation a year (NOAA 1991–2020 normals).