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

Planting zone for 62948 — Herrin, IL

ZIP code 62948 (Herrin, Williamson County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 9 and the first fall frost October 22.

Where ZIP 62948 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.

Zone7a0 to 5 °F
Coldest night−17.8 to −15 °C
Last frostApr 9
First frostOct 22
2012 zone6b

Was 6b 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 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Herrin, 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 Herrin, IL

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 9median — 50% chance of a later frost
Safe for tender plantsApril 25only 10% chance of frost after
First fall frostOctober 22median — 10% chance by Oct 10
Growing season195 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 29 and returns around November 1.

From the NOAA station Carbondale Sewage Plt, IL — 10 miles away, elevation 390 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 62948

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 26 – Mar 12
SpinachSow outdoors · Feb 26 – Mar 19
Broccoli, cabbageStart indoors · Jan 29 – Feb 12
Broccoli, cabbageTransplant · Mar 19 – Apr 2
Onion setsPlant outdoors · Mar 12 – Mar 26
PotatoesPlant outdoors · Mar 19 – Apr 2
LettuceSow outdoors · Mar 12 – Mar 26
Carrots, beetsSow outdoors · Mar 19 – Apr 2
TomatoesStart indoors · Feb 12 – Feb 26
TomatoesTransplant · Apr 16 – Apr 30
Peppers, eggplantStart indoors · Jan 29 – Feb 12
Peppers, eggplantTransplant · Apr 23 – May 7
BeansSow outdoors · Apr 16 – Apr 30
Sweet cornSow outdoors · Apr 16 – Apr 30
Cucumbers, squashSow outdoors · Apr 16 – Apr 30
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 9) 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 62948 came on Mar 2 — 10 days earlier than the 1991–2020 average (Mar 12).

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 7a in Illinois

633 plants native to the lower 48 states, recorded in Illinois, and rated by the USDA to survive 0 °F or colder — the bottom of zone 7a. Each links to its USDA PLANTS profile.

Trees 81

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 110

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 226

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 186

American beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °Farctic brome3 ft · blooms early summer · low shade tolerance · to −33 °Fautumn bluegrass1.5 ft · blooms late spring · medium shade tolerance · to −8 °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 °F

Vines 13

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °FAmerican wisteria50 ft · blooms spring · low shade tolerance · to −3 °Fcatbird grape30 ft · blooms late spring · medium shade tolerance · to −13 °Fcupseed30 ft · blooms late spring · low shade tolerance · to −3 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °Ffrost grape83 ft · blooms late spring · medium 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 Herrin, IL.

Soil in Herrin, IL

The soil mapped at the center of ZIP 62948 is Cisne — silt loam, poorly drained.

TextureSilt loama good balance for most vegetables
pH5.8moderately acidic; most vegetables like 6.0–7.0
DrainagePoorly drainedconsider raised beds
Organic matter1.75%low — add compost
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classPrime farmland if drainedUSDA classification

Map unit: Cisne silt loam, bench, 0 to 2 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 62948; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Herrin, IL

Summer high88 °Faverage high, July
Winter low23 °Faverage low, January
Hot days38days a year at 90 °F or more
Freezing nights103nights a year at 32 °F or less
Growing degree days4,111base 50 °F — the season’s usable heat
Longest day14 h 47 mindaylight on June 21
Shortest day9 h 32 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation47.8 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 41 °F, low 23 °F 41°23° JanFebruary: average high 46 °F, low 26 °F 46°26° FebMarch: average high 56 °F, low 35 °F 56°35° MarApril: average high 68 °F, low 44 °F 68°44° AprMay: average high 77 °F, low 55 °F 77°55° MayJune: average high 85 °F, low 64 °F 85°64° JunJuly: average high 88 °F, low 68 °F 88°68° JulAugust: average high 87 °F, low 65 °F 87°65° AugSeptember: average high 81 °F, low 56 °F 81°56° SepOctober: average high 70 °F, low 44 °F 70°44° OctNovember: average high 56 °F, low 35 °F 56°35° NovDecember: average high 45 °F, low 27 °F 45°27° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 3.28 in precipitation 3.3 JanFebruary: 3.10 in precipitation 3.1 FebMarch: 4.33 in precipitation 4.3 MarApril: 5.30 in precipitation 5.3 AprMay: 5.23 in precipitation 5.2 MayJune: 4.62 in precipitation 4.6 JunJuly: 4.09 in precipitation 4.1 JulAugust: 3.36 in precipitation 3.4 AugSeptember: 3.20 in precipitation 3.2 SepOctober: 3.60 in precipitation 3.6 OctNovember: 4.16 in precipitation 4.2 NovDecember: 3.49 in precipitation 3.5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Carbondale Sewage Plt, IL (10 mi away); precipitation: Bush 2.0 Ese, IL (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

628417a
Freeman Spur, IL · 3 mi
629337a
Energy, IL · 3 mi
629217a
Colp, IL · 3 mi
629997a
Zeigler, IL · 4 mi
629187a
Carterville, IL · 4 mi
629517a
Johnston City, IL · 5 mi
629157a
Cambria, IL · 6 mi
629497a
Hurst, IL · 6 mi

Illinois planting zones →

Questions about 62948

What planting zone is ZIP code 62948?

ZIP code 62948 (Herrin, IL) is in USDA hardiness zone 7a on the 2023 map: the coldest night of an average winter reaches 0 to 5 °F (−17.8 to −15 °C).

When is the last frost in Herrin, IL?

The median last spring frost (32 °F) near 62948 is April 9; after April 25 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Carbondale Sewage Plt station.

When is the first frost in Herrin, IL?

The median first fall frost near 62948 is October 22, giving a median frost-free growing season of 195 days.

When should I plant tomatoes in 62948?

Start tomato seeds indoors around Feb 12 – Feb 26 and set transplants outside around Apr 16 – Apr 30, one to three weeks after the median last frost.

How much rain and snow does 62948 get?

About 47.8 inches of precipitation a year (NOAA 1991–2020 normals, Bush 2.0 Ese station).

How hot do summers get in Herrin, IL?

The average high peaks at 88 °F in July, with about 38 days a year at 90 °F or more.

What kind of soil does 62948 have?

The USDA soil survey maps Cisne at the center of ZIP 62948: silt loam, poorly drained, pH about 5.8 (moderately acidic).

Did spring come early in Herrin, IL in 2026?

Spring leaf-out near 62948 came on Mar 2 in 2026, 10 days earlier than the 1991–2020 average (Mar 12), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Herrin, IL?

Intermediate onions: the longest day near 62948 is 14 h 47 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 62948 change?

Yes. The 2012 USDA map put 62948 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.