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

Planting zone for 62828 — Dahlgren, IL

ZIP code 62828 (Dahlgren, Hamilton County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 11 and the first fall frost October 21.

Where ZIP 62828 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 11
First frostOct 21
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 Dahlgren, 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 Dahlgren, IL

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 11median — 50% chance of a later frost
Safe for tender plantsApril 26only 10% chance of frost after
First fall frostOctober 21median — 10% chance by Oct 6
Growing season190 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 1 and returns around October 30.

From the NOAA station Mcleansboro, IL — 8 miles away, elevation 446 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 62828

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 28 – Mar 14
SpinachSow outdoors · Feb 28 – Mar 21
Broccoli, cabbageStart indoors · Jan 31 – Feb 14
Broccoli, cabbageTransplant · Mar 21 – Apr 4
Onion setsPlant outdoors · Mar 14 – Mar 28
PotatoesPlant outdoors · Mar 21 – Apr 4
LettuceSow outdoors · Mar 14 – Mar 28
Carrots, beetsSow outdoors · Mar 21 – Apr 4
TomatoesStart indoors · Feb 14 – Feb 28
TomatoesTransplant · Apr 18 – May 2
Peppers, eggplantStart indoors · Jan 31 – Feb 14
Peppers, eggplantTransplant · Apr 25 – May 9
BeansSow outdoors · Apr 18 – May 2
Sweet cornSow outdoors · Apr 18 – May 2
Cucumbers, squashSow outdoors · Apr 18 – May 2
Fall lettuce, spinachSow outdoors · Aug 26 – Sep 9
GarlicPlant cloves · Oct 7 – Nov 11
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 11) and first fall frost (Oct 21) 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 62828 came on Mar 5 — 10 days earlier than the 1991–2020 average (Mar 15).

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 6b in Illinois

620 plants native to the lower 48 states, recorded in Illinois, and rated by the USDA to survive −5 °F or colder — the bottom of zone 6b. Each links to its USDA PLANTS profile.

Trees 80

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 222

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 182

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 11

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 °Fgraybark grape50 ft · blooms late spring · medium shade tolerance · to −8 °Fheartleaf peppervine2 ft · blooms late spring · low shade tolerance · to −8 °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 Dahlgren, IL.

Soil in Dahlgren, IL

The soil mapped at the center of ZIP 62828 is Bluford — silt loam, somewhat poorly drained.

TextureSilt loama good balance for most vegetables
pH6.6neutral; most vegetables like 6.0–7.0
DrainageSomewhat poorly drainedconsider raised beds
Organic matter1.75%low — add compost
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classPrime farmland if drainedUSDA classification

Map unit: Bluford silt loam, 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 62828; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Dahlgren, IL

Summer high89 °Faverage high, July
Winter low22 °Faverage low, January
Hot days43days a year at 90 °F or more
Freezing nights110nights a year at 32 °F or less
Growing degree days4,039base 50 °F — the season’s usable heat
Longest day14 h 49 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
Precipitation47 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 22 °F 41°22° JanFebruary: average high 46 °F, low 24 °F 46°24° FebMarch: average high 56 °F, low 34 °F 56°34° 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 63 °F 85°63° JunJuly: average high 89 °F, low 66 °F 89°66° JulAugust: average high 88 °F, low 63 °F 88°63° AugSeptember: average high 82 °F, low 55 °F 82°55° SepOctober: average high 70 °F, low 43 °F 70°43° OctNovember: average high 56 °F, low 33 °F 56°33° NovDecember: average high 45 °F, low 26 °F 45°26° Dec

Precipitation by month inches

0″2″4″6″January: 3.06 in precipitation 3.1 JanFebruary: 2.65 in precipitation 2.6 FebMarch: 3.97 in precipitation 4.0 MarApril: 5.25 in precipitation 5.3 AprMay: 6.08 in precipitation 6.1 MayJune: 4.66 in precipitation 4.7 JunJuly: 3.61 in precipitation 3.6 JulAugust: 3.51 in precipitation 3.5 AugSeptember: 3.55 in precipitation 3.5 SepOctober: 3.77 in precipitation 3.8 OctNovember: 3.66 in precipitation 3.7 NovDecember: 3.18 in precipitation 3.2 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Mcleansboro, IL (8 mi away); precipitation: Belle Rive 1.7 Nne, IL (8 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

628106b
Belle Rive, IL · 8 mi
628956b
Wayne City, IL · 8 mi
628596b
Mc Leansboro, IL · 9 mi
628726b
Opdyke, IL · 12 mi
628877a
Springerton, IL · 13 mi
628606b
Macedonia, IL · 13 mi
628366b
Ewing, IL · 13 mi
628866b
Sims, IL · 13 mi

Illinois planting zones →

Questions about 62828

What planting zone is ZIP code 62828?

ZIP code 62828 (Dahlgren, 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 Dahlgren, IL?

The median last spring frost (32 °F) near 62828 is April 11; after April 26 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Mcleansboro station.

When is the first frost in Dahlgren, IL?

The median first fall frost near 62828 is October 21, giving a median frost-free growing season of 190 days.

When should I plant tomatoes in 62828?

Start tomato seeds indoors around Feb 14 – Feb 28 and set transplants outside around Apr 18 – May 2, one to three weeks after the median last frost.

How much rain and snow does 62828 get?

About 47 inches of precipitation a year (NOAA 1991–2020 normals, Belle Rive 1.7 Nne station).

How hot do summers get in Dahlgren, IL?

The average high peaks at 89 °F in July, with about 43 days a year at 90 °F or more.

What kind of soil does 62828 have?

The USDA soil survey maps Bluford at the center of ZIP 62828: silt loam, somewhat poorly drained, pH about 6.6 (neutral).

Did spring come early in Dahlgren, IL in 2026?

Spring leaf-out near 62828 came on Mar 5 in 2026, 10 days earlier than the 1991–2020 average (Mar 15), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Dahlgren, IL?

Intermediate onions: the longest day near 62828 is 14 h 49 min, so day-neutral types bulb best; long-day varieties may not bulb fully.