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

Planting zone for 62255 — Lenzburg, IL

ZIP code 62255 (Lenzburg, St. Clair County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 12 and the first fall frost October 22.

Where ZIP 62255 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.

Zone6b−5 to 0 °F
Coldest night−20.6 to −17.8 °C
Last frostApr 12
First frostOct 22
2012 zone6b

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Lenzburg, 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 Lenzburg, IL

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 12median — 50% chance of a later frost
Safe for tender plantsApril 29only 10% chance of frost after
First fall frostOctober 22median — 10% chance by Oct 7
Growing season191 daysfrost-free, median

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

From the NOAA station Sparta 1 W, IL — 14 miles away, elevation 535 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 62255

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 1 – Mar 15
SpinachSow outdoors · Mar 1 – Mar 22
Broccoli, cabbageStart indoors · Feb 1 – Feb 15
Broccoli, cabbageTransplant · Mar 22 – Apr 5
Onion setsPlant outdoors · Mar 15 – Mar 29
PotatoesPlant outdoors · Mar 22 – Apr 5
LettuceSow outdoors · Mar 15 – Mar 29
Carrots, beetsSow outdoors · Mar 22 – Apr 5
TomatoesStart indoors · Feb 15 – Mar 1
TomatoesTransplant · Apr 19 – May 3
Peppers, eggplantStart indoors · Feb 1 – Feb 15
Peppers, eggplantTransplant · Apr 26 – May 10
BeansSow outdoors · Apr 19 – May 3
Sweet cornSow outdoors · Apr 19 – May 3
Cucumbers, squashSow outdoors · Apr 19 – May 3
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 12) 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 62255 came on Mar 3 — 10 days earlier than the 1991–2020 average (Mar 13).

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).

Soil in Lenzburg, IL

The soil mapped at the center of ZIP 62255 is Okaw — silt loam, poorly drained.

TextureSilt loama good balance for most vegetables
pH5.9moderately acidic; most vegetables like 6.0–7.0
DrainagePoorly drainedconsider raised beds
Organic matter1.5%low — add compost
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Okaw silt loam, 0 to 2 percent slopes, occasionally flooded.

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 62255; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Lenzburg, IL

Summer high88 °Faverage high, July
Winter low22 °Faverage low, January
Hot days35days a year at 90 °F or more
Freezing nights109nights a year at 32 °F or less
Growing degree days3,944base 50 °F — the season’s usable heat
Longest day14 h 50 mindaylight on June 21
Shortest day9 h 30 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation45 inper year, rain and melted snow
Snowfall12 inper year; 12 days with snow on the ground

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 40 °F, low 22 °F 40°22° JanFebruary: average high 45 °F, low 25 °F 45°25° FebMarch: average high 56 °F, low 33 °F 56°33° MarApril: average high 67 °F, low 43 °F 67°43° AprMay: average high 76 °F, low 54 °F 76°54° MayJune: average high 84 °F, low 62 °F 84°62° JunJuly: average high 88 °F, low 66 °F 88°66° JulAugust: average high 87 °F, low 64 °F 87°64° AugSeptember: average high 81 °F, low 55 °F 81°55° SepOctober: average high 70 °F, low 44 °F 70°44° OctNovember: average high 56 °F, low 35 °F 56°35° NovDecember: average high 44 °F, low 26 °F 44°26° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″6″January: 2.77 in precipitation, 4 in snowfall 2.8❄4 JanFebruary: 2.43 in precipitation, 3.9 in snowfall 2.4❄4 FebMarch: 3.61 in precipitation, 1.4 in snowfall 3.6❄1 MarApril: 4.94 in precipitation 4.9 AprMay: 4.93 in precipitation 4.9 MayJune: 5.17 in precipitation 5.2 JunJuly: 4.80 in precipitation 4.8 JulAugust: 3.29 in precipitation 3.3 AugSeptember: 3.37 in precipitation 3.4 SepOctober: 2.98 in precipitation 3.0 OctNovember: 3.78 in precipitation, 0.2 in snowfall 3.8 NovDecember: 2.92 in precipitation, 2.1 in snowfall 2.9❄2 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Sparta 1 W, IL (14 mi away); precipitation: New Athens, IL (5 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

5 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

622577a
Marissa, IL · 4 mi
622826b
Saint Libory, IL · 5 mi
622647a
New Athens, IL · 6 mi
622927a
Tilden, IL · 9 mi
622437a
Freeburg, IL · 9 mi
622177a
Baldwin, IL · 10 mi
622586b
Mascoutah, IL · 10 mi
622146b
Addieville, IL · 11 mi

Illinois planting zones →

Questions about 62255

What planting zone is ZIP code 62255?

ZIP code 62255 (Lenzburg, IL) is in USDA hardiness zone 6b on the 2023 map: the coldest night of an average winter reaches −5 to 0 °F (−20.6 to −17.8 °C).

When is the last frost in Lenzburg, IL?

The median last spring frost (32 °F) near 62255 is April 12; after April 29 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Sparta 1 W station.

When is the first frost in Lenzburg, IL?

The median first fall frost near 62255 is October 22, giving a median frost-free growing season of 191 days.

When should I plant tomatoes in 62255?

Start tomato seeds indoors around Feb 15 – Mar 1 and set transplants outside around Apr 19 – May 3, one to three weeks after the median last frost.

How much rain and snow does 62255 get?

About 45 inches of precipitation a year and 12 inches of snowfall (NOAA 1991–2020 normals, New Athens station).

How hot do summers get in Lenzburg, IL?

The average high peaks at 88 °F in July, with about 35 days a year at 90 °F or more.

What kind of soil does 62255 have?

The USDA soil survey maps Okaw at the center of ZIP 62255: silt loam, poorly drained, pH about 5.9 (moderately acidic).

Did spring come early in Lenzburg, IL in 2026?

Spring leaf-out near 62255 came on Mar 3 in 2026, 10 days earlier than the 1991–2020 average (Mar 13), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Lenzburg, IL?

Intermediate onions: the longest day near 62255 is 14 h 50 min, so day-neutral types bulb best; long-day varieties may not bulb fully.