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

Planting zone for 60441 — Lockport, IL

ZIP code 60441 (Lockport, Will County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is April 20 and the first fall frost October 22.

Where ZIP 60441 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 20
First frostOct 22
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 Lockport, 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 Lockport, IL

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 20median — 50% chance of a later frost
Safe for tender plantsMay 6only 10% chance of frost after
First fall frostOctober 22median — 10% chance by Oct 7
Growing season184 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 8 and returns around November 1.

From the NOAA station Romeoville WFO, IL — 2 miles away, elevation 659 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 60441

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 9 – Mar 23
SpinachSow outdoors · Mar 9 – Mar 30
Broccoli, cabbageStart indoors · Feb 9 – Feb 23
Broccoli, cabbageTransplant · Mar 30 – Apr 13
Onion setsPlant outdoors · Mar 23 – Apr 6
PotatoesPlant outdoors · Mar 30 – Apr 13
LettuceSow outdoors · Mar 23 – Apr 6
Carrots, beetsSow outdoors · Mar 30 – Apr 13
TomatoesStart indoors · Feb 23 – Mar 9
TomatoesTransplant · Apr 27 – May 11
Peppers, eggplantStart indoors · Feb 9 – Feb 23
Peppers, eggplantTransplant · May 4 – May 18
BeansSow outdoors · Apr 27 – May 11
Sweet cornSow outdoors · Apr 27 – May 11
Cucumbers, squashSow outdoors · Apr 27 – May 11
Fall lettuce, spinachSow outdoors · Aug 27 – Sep 10
GarlicPlant cloves · Oct 8 – Nov 12
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 20) and first fall frost (Oct 22) 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 60441 came on Mar 20 — 15 days earlier than the 1991–2020 average (Apr 4).

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 Lockport, IL.

Soil in Lockport, IL

The soil mapped at the center of ZIP 60441 is Blount — silt loam, somewhat poorly drained.

TextureSilt loama good balance for most vegetables
pH6.0slightly acidic; most vegetables like 6.0–7.0
DrainageSomewhat poorly drainedconsider raised beds
Organic matter2.5%moderate
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classprime farmlandUSDA classification

Map unit: Blount silt loam, Lake Michigan Lobe, 2 to 4 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 60441; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Lockport, IL

Summer high85 °Faverage high, July
Winter low16 °Faverage low, January
Hot days16days a year at 90 °F or more
Freezing nights123nights a year at 32 °F or less
Growing degree days3,305base 50 °F — the season’s usable heat
Longest day15 h 12 mindaylight on June 21
Shortest day9 h 09 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation40.3 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 32 °F, low 16 °F 32°16° JanFebruary: average high 36 °F, low 20 °F 36°20° FebMarch: average high 49 °F, low 30 °F 49°30° MarApril: average high 61 °F, low 40 °F 61°40° AprMay: average high 72 °F, low 50 °F 72°50° MayJune: average high 82 °F, low 60 °F 82°60° JunJuly: average high 85 °F, low 65 °F 85°65° JulAugust: average high 83 °F, low 63 °F 83°63° AugSeptember: average high 76 °F, low 55 °F 76°55° SepOctober: average high 64 °F, low 44 °F 64°44° 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

0″1″2″3″4″5″January: 2.14 in precipitation 2.1 JanFebruary: 1.94 in precipitation 1.9 FebMarch: 2.79 in precipitation 2.8 MarApril: 3.87 in precipitation 3.9 AprMay: 4.53 in precipitation 4.5 MayJune: 4.62 in precipitation 4.6 JunJuly: 4.57 in precipitation 4.6 JulAugust: 4.08 in precipitation 4.1 AugSeptember: 3.32 in precipitation 3.3 SepOctober: 3.56 in precipitation 3.6 OctNovember: 2.66 in precipitation 2.7 NovDecember: 2.24 in precipitation 2.2 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Romeoville WFO, IL (2 mi away); precipitation: Lockport 1.3 Se, IL (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

604326a
Joliet, IL · 4 mi
604466a
Romeoville, IL · 4 mi
604036a
Crest Hill, IL · 4 mi
604916a
Homer Glen, IL · 5 mi
604346a
Joliet, IL · 5 mi
604356a
Joliet, IL · 5 mi
604336a
Joliet, IL · 7 mi
604396a
Lemont, IL · 7 mi

Illinois planting zones →

Questions about 60441

What planting zone is ZIP code 60441?

ZIP code 60441 (Lockport, 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 Lockport, IL?

The median last spring frost (32 °F) near 60441 is April 20; after May 6 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Romeoville WFO station.

When is the first frost in Lockport, IL?

The median first fall frost near 60441 is October 22, giving a median frost-free growing season of 184 days.

When should I plant tomatoes in 60441?

Start tomato seeds indoors around Feb 23 – Mar 9 and set transplants outside around Apr 27 – May 11, one to three weeks after the median last frost.

How much rain and snow does 60441 get?

About 40.3 inches of precipitation a year (NOAA 1991–2020 normals, Lockport 1.3 Se station).

How hot do summers get in Lockport, IL?

The average high peaks at 85 °F in July, with about 16 days a year at 90 °F or more.

What kind of soil does 60441 have?

The USDA soil survey maps Blount at the center of ZIP 60441: silt loam, somewhat poorly drained, pH about 6.0 (slightly acidic).

Did spring come early in Lockport, IL in 2026?

Spring leaf-out near 60441 came on Mar 20 in 2026, 15 days earlier than the 1991–2020 average (Apr 4), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Lockport, IL?

Long-day onions: the longest day near 60441 is 15 h 12 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 60441 change?

Yes. The 2012 USDA map put 60441 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.