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

Planting zone for 62908 — Belknap, IL

ZIP code 62908 (Belknap, Johnson County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 3 and the first fall frost November 5.

Where ZIP 62908 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 3
First frostNov 5
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 Belknap, 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 Belknap, IL

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 3median — 50% chance of a later frost
Safe for tender plantsApril 21only 10% chance of frost after
First fall frostNovember 5median — 10% chance by Oct 23
Growing season216 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 22 and returns around November 17.

From the NOAA station Grand Chain Dam 53, IL — 12 miles away, elevation 384 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 62908

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 20 – Mar 6
SpinachSow outdoors · Feb 20 – Mar 13
Broccoli, cabbageStart indoors · Jan 23 – Feb 6
Broccoli, cabbageTransplant · Mar 13 – Mar 27
Onion setsPlant outdoors · Mar 6 – Mar 20
PotatoesPlant outdoors · Mar 13 – Mar 27
LettuceSow outdoors · Mar 6 – Mar 20
Carrots, beetsSow outdoors · Mar 13 – Mar 27
TomatoesStart indoors · Feb 6 – Feb 20
TomatoesTransplant · Apr 10 – Apr 24
Peppers, eggplantStart indoors · Jan 23 – Feb 6
Peppers, eggplantTransplant · Apr 17 – May 1
BeansSow outdoors · Apr 10 – Apr 24
Sweet cornSow outdoors · Apr 10 – Apr 24
Cucumbers, squashSow outdoors · Apr 10 – Apr 24
Fall lettuce, spinachSow outdoors · Sep 10 – Sep 24
GarlicPlant cloves · Oct 22 – Nov 26
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 3) and first fall frost (Nov 5) 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 62908 came on Mar 1 — 6 days earlier than the 1991–2020 average (Mar 7).

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 Belknap, IL.

Soil in Belknap, IL

The soil mapped at the center of ZIP 62908 is Wheeling — silt loam, well drained.

TextureSilt loama good balance for most vegetables
pH5.8moderately acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2%moderate
Hydrologic groupBwater soaks in moderately
Farmland classFarmland of statewide importanceUSDA classification

Map unit: Wheeling silt loam, 5 to 10 percent slopes, eroded, rarely 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 62908; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Belknap, IL

Summer high89 °Faverage high, July
Winter low26 °Faverage low, January
Hot days41days a year at 90 °F or more
Freezing nights80nights a year at 32 °F or less
Growing degree days4,461base 50 °F — the season’s usable heat
Longest day14 h 44 mindaylight on June 21
Shortest day9 h 35 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation51.6 inper year, rain and melted snow

Average high and low, by month

20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 43 °F, low 26 °F 43°26° JanFebruary: average high 48 °F, low 30 °F 48°30° FebMarch: average high 57 °F, low 37 °F 57°37° MarApril: average high 68 °F, low 47 °F 68°47° AprMay: average high 77 °F, low 56 °F 77°56° MayJune: average high 86 °F, low 65 °F 86°65° JunJuly: average high 89 °F, low 69 °F 89°69° JulAugust: average high 89 °F, low 67 °F 89°67° AugSeptember: average high 83 °F, low 60 °F 83°60° SepOctober: average high 71 °F, low 48 °F 71°48° OctNovember: average high 58 °F, low 39 °F 58°39° NovDecember: average high 47 °F, low 31 °F 47°31° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 3.62 in precipitation 3.6 JanFebruary: 3.63 in precipitation 3.6 FebMarch: 4.85 in precipitation 4.8 MarApril: 5.17 in precipitation 5.2 AprMay: 5.10 in precipitation 5.1 MayJune: 4.59 in precipitation 4.6 JunJuly: 3.92 in precipitation 3.9 JulAugust: 3.68 in precipitation 3.7 AugSeptember: 4.16 in precipitation 4.2 SepOctober: 3.72 in precipitation 3.7 OctNovember: 4.25 in precipitation 4.3 NovDecember: 4.91 in precipitation 4.9 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Grand Chain Dam 53, IL (12 mi away); precipitation: Belknap 11.1 Ese, IL (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

629567a
Karnak, IL · 4 mi
629537a
Joppa, IL · 7 mi
629437a
Grantsburg, IL · 7 mi
629417a
Grand Chain, IL · 7 mi
629957a
Vienna, IL · 8 mi
629607a
Metropolis, IL · 9 mi
629237a
Cypress, IL · 10 mi
629737a
Perks, IL · 12 mi

Illinois planting zones →

Questions about 62908

What planting zone is ZIP code 62908?

ZIP code 62908 (Belknap, 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 Belknap, IL?

The median last spring frost (32 °F) near 62908 is April 3; after April 21 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Grand Chain Dam 53 station.

When is the first frost in Belknap, IL?

The median first fall frost near 62908 is November 5, giving a median frost-free growing season of 216 days.

When should I plant tomatoes in 62908?

Start tomato seeds indoors around Feb 6 – Feb 20 and set transplants outside around Apr 10 – Apr 24, one to three weeks after the median last frost.

How much rain and snow does 62908 get?

About 51.6 inches of precipitation a year (NOAA 1991–2020 normals, Belknap 11.1 Ese station).

How hot do summers get in Belknap, IL?

The average high peaks at 89 °F in July, with about 41 days a year at 90 °F or more.

What kind of soil does 62908 have?

The USDA soil survey maps Wheeling at the center of ZIP 62908: silt loam, well drained, pH about 5.8 (moderately acidic).

Did spring come early in Belknap, IL in 2026?

Spring leaf-out near 62908 came on Mar 1 in 2026, 6 days earlier than the 1991–2020 average (Mar 7), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Belknap, IL?

Intermediate onions: the longest day near 62908 is 14 h 44 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 62908 change?

Yes. The 2012 USDA map put 62908 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.