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

Planting zone for 62639 — Frederick, IL

ZIP code 62639 (Frederick, Schuyler County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is April 16 and the first fall frost October 23.

Where ZIP 62639 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 16
First frostOct 23
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 Frederick, 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 Frederick, IL

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 16median — 50% chance of a later frost
Safe for tender plantsMay 3only 10% chance of frost after
First fall frostOctober 23median — 10% chance by Oct 10
Growing season189 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 4 and returns around November 1.

From the NOAA station Rushville, IL — 7 miles away, elevation 673 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 62639

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 5 – Mar 19
SpinachSow outdoors · Mar 5 – Mar 26
Broccoli, cabbageStart indoors · Feb 5 – Feb 19
Broccoli, cabbageTransplant · Mar 26 – Apr 9
Onion setsPlant outdoors · Mar 19 – Apr 2
PotatoesPlant outdoors · Mar 26 – Apr 9
LettuceSow outdoors · Mar 19 – Apr 2
Carrots, beetsSow outdoors · Mar 26 – Apr 9
TomatoesStart indoors · Feb 19 – Mar 5
TomatoesTransplant · Apr 23 – May 7
Peppers, eggplantStart indoors · Feb 5 – Feb 19
Peppers, eggplantTransplant · Apr 30 – May 14
BeansSow outdoors · Apr 23 – May 7
Sweet cornSow outdoors · Apr 23 – May 7
Cucumbers, squashSow outdoors · Apr 23 – May 7
Fall lettuce, spinachSow outdoors · Aug 28 – Sep 11
GarlicPlant cloves · Oct 9 – Nov 13
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 16) and first fall frost (Oct 23) 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 62639 came on Mar 10 — 16 days earlier than the 1991–2020 average (Mar 26).

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 Frederick, IL.

Soil in Frederick, IL

The soil mapped at the center of ZIP 62639 is Titus — silty clay loam, poorly drained.

TextureSilty clay loamholds water and nutrients; slow to drain and warm up
pH6.7neutral; most vegetables like 6.0–7.0
DrainagePoorly drainedconsider raised beds
Organic matter3%moderate
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classPrime farmland if drainedUSDA classification

Map unit: Titus silty clay 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 62639; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Frederick, IL

Summer high85 °Faverage high, July
Winter low17 °Faverage low, January
Hot days21days a year at 90 °F or more
Freezing nights121nights a year at 32 °F or less
Growing degree days3,433base 50 °F — the season’s usable heat
Longest day15 h 01 mindaylight on June 21
Shortest day9 h 19 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation36 inper year, rain and melted snow
Snowfall12 inper year

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 33 °F, low 17 °F 33°17° JanFebruary: average high 38 °F, low 21 °F 38°21° FebMarch: average high 50 °F, low 31 °F 50°31° MarApril: average high 62 °F, low 42 °F 62°42° AprMay: average high 72 °F, low 52 °F 72°52° MayJune: average high 81 °F, low 62 °F 81°62° JunJuly: average high 85 °F, low 65 °F 85°65° JulAugust: average high 83 °F, low 63 °F 83°63° AugSeptember: average high 77 °F, low 55 °F 77°55° SepOctober: average high 65 °F, low 44 °F 65°44° OctNovember: average high 50 °F, low 33 °F 50°33° NovDecember: average high 39 °F, low 23 °F 39°23° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″January: 1.86 in precipitation, 3.3 in snowfall 1.9❄3 JanFebruary: 1.76 in precipitation, 4.5 in snowfall 1.8❄5 FebMarch: 1.94 in precipitation, 1.3 in snowfall 1.9❄1 MarApril: 3.77 in precipitation 3.8 AprMay: 4.07 in precipitation 4.1 MayJune: 4.37 in precipitation 4.4 JunJuly: 3.68 in precipitation 3.7 JulAugust: 3.41 in precipitation 3.4 AugSeptember: 3.15 in precipitation 3.1 SepOctober: 3.19 in precipitation 3.2 OctNovember: 2.60 in precipitation, 0.2 in snowfall 2.6 NovDecember: 2.17 in precipitation, 2.5 in snowfall 2.2❄3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Rushville, IL (7 mi away); precipitation: Beardstown, IL (3 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

626186a
Beardstown, IL · 5 mi
626816a
Rushville, IL · 7 mi
626226a
Bluff Springs, IL · 9 mi
626246a
Browning, IL · 11 mi
626116a
Arenzville, IL · 12 mi
623786a
Versailles, IL · 12 mi
626916a
Virginia, IL · 15 mi
623196a
Camden, IL · 15 mi

Illinois planting zones →

Questions about 62639

What planting zone is ZIP code 62639?

ZIP code 62639 (Frederick, 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 Frederick, IL?

The median last spring frost (32 °F) near 62639 is April 16; after May 3 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Rushville station.

When is the first frost in Frederick, IL?

The median first fall frost near 62639 is October 23, giving a median frost-free growing season of 189 days.

When should I plant tomatoes in 62639?

Start tomato seeds indoors around Feb 19 – Mar 5 and set transplants outside around Apr 23 – May 7, one to three weeks after the median last frost.

How much rain and snow does 62639 get?

About 36 inches of precipitation a year and 12 inches of snowfall (NOAA 1991–2020 normals, Beardstown station).

How hot do summers get in Frederick, IL?

The average high peaks at 85 °F in July, with about 21 days a year at 90 °F or more.

What kind of soil does 62639 have?

The USDA soil survey maps Titus at the center of ZIP 62639: silty clay loam, poorly drained, pH about 6.7 (neutral).

Did spring come early in Frederick, IL in 2026?

Spring leaf-out near 62639 came on Mar 10 in 2026, 16 days earlier than the 1991–2020 average (Mar 26), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Frederick, IL?

Long-day onions: the longest day near 62639 is 15 h 01 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 62639 change?

Yes. The 2012 USDA map put 62639 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.