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

Planting zone for 62523 — Decatur, IL

ZIP code 62523 (Decatur, Macon County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is April 14 and the first fall frost October 24.

Where ZIP 62523 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 14
First frostOct 24
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 Decatur, 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 Decatur, 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 1only 10% chance of frost after
First fall frostOctober 24median — 10% chance by Oct 11
Growing season192 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 3 and returns around November 3.

From the NOAA station Decatur Wtp, IL — within 1 mile, elevation 640 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 62523

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 62523 came on Mar 10 — 15 days earlier than the 1991–2020 average (Mar 25).

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 Decatur, IL.

Soil in Decatur, IL

The soil mapped at the center of ZIP 62523 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 62523; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Decatur, IL

Summer high85 °Faverage high, July
Winter low20 °Faverage low, January
Hot days26days a year at 90 °F or more
Freezing nights110nights a year at 32 °F or less
Growing degree days3,664base 50 °F — the season’s usable heat
Longest day15 h 00 mindaylight on June 21
Shortest day9 h 20 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation40.4 inper year, rain and melted snow
Snowfall14 inper year

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 34 °F, low 20 °F 34°20° JanFebruary: average high 39 °F, low 24 °F 39°24° FebMarch: average high 51 °F, low 33 °F 51°33° MarApril: average high 63 °F, low 43 °F 63°43° AprMay: average high 74 °F, low 54 °F 74°54° MayJune: average high 82 °F, low 63 °F 82°63° JunJuly: average high 85 °F, low 67 °F 85°67° JulAugust: average high 84 °F, low 65 °F 84°65° AugSeptember: average high 78 °F, low 57 °F 78°57° SepOctober: average high 65 °F, low 46 °F 65°46° OctNovember: average high 50 °F, low 34 °F 50°34° NovDecember: average high 39 °F, low 25 °F 39°25° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″January: 2.40 in precipitation, 5.9 in snowfall 2.4❄6 JanFebruary: 2.00 in precipitation, 2.5 in snowfall 2.0❄3 FebMarch: 2.64 in precipitation, 0.9 in snowfall 2.6❄1 MarApril: 4.12 in precipitation, 0.4 in snowfall 4.1 AprMay: 4.95 in precipitation 5.0 MayJune: 4.73 in precipitation 4.7 JunJuly: 4.00 in precipitation 4.0 JulAugust: 3.50 in precipitation 3.5 AugSeptember: 3.08 in precipitation 3.1 SepOctober: 3.41 in precipitation 3.4 OctNovember: 3.21 in precipitation, 0.4 in snowfall 3.2 NovDecember: 2.40 in precipitation, 3.5 in snowfall 2.4❄4 Dec

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

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

625246a
Decatur, IL · 2 mi
625256a
Decatur, IL · 2 mi
625216a
Decatur, IL · 3 mi
625266a
Decatur, IL · 4 mi
625326a
Elwin, IL · 5 mi
625226a
Decatur, IL · 5 mi
625356a
Forsyth, IL · 6 mi
625496a
Mt Zion, IL · 7 mi

All 6 ZIP codes in Decatur → · Illinois planting zones →

Questions about 62523

What planting zone is ZIP code 62523?

ZIP code 62523 (Decatur, 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 Decatur, IL?

The median last spring frost (32 °F) near 62523 is April 14; after May 1 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Decatur Wtp station.

When is the first frost in Decatur, IL?

The median first fall frost near 62523 is October 24, giving a median frost-free growing season of 192 days.

When should I plant tomatoes in 62523?

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 62523 get?

About 40.4 inches of precipitation a year and 14 inches of snowfall (NOAA 1991–2020 normals, Decatur Wtp station).

How hot do summers get in Decatur, IL?

The average high peaks at 85 °F in July, with about 26 days a year at 90 °F or more.

What kind of soil does 62523 have?

The USDA soil survey maps Orthents at the center of ZIP 62523: silty clay, moderately well drained, pH about 6.7 (neutral).

Did spring come early in Decatur, IL in 2026?

Spring leaf-out near 62523 came on Mar 10 in 2026, 15 days earlier than the 1991–2020 average (Mar 25), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Decatur, IL?

Intermediate onions: the longest day near 62523 is 15 h 00 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 62523 change?

Yes. The 2012 USDA map put 62523 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.