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

Planting zone for 61437 — Gladstone, IL

ZIP code 61437 (Gladstone, Henderson County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is April 8 and the first fall frost October 29.

Where ZIP 61437 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 8
First frostOct 29
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 Gladstone, 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 Gladstone, IL

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 8median — 50% chance of a later frost
Safe for tender plantsApril 23only 10% chance of frost after
First fall frostOctober 29median — 10% chance by Oct 17
Growing season202 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 31 and returns around November 7.

From the NOAA station Gladstone Dam 18, IL — 3 miles away, elevation 538 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 61437

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 25 – Mar 11
SpinachSow outdoors · Feb 25 – Mar 18
Broccoli, cabbageStart indoors · Jan 28 – Feb 11
Broccoli, cabbageTransplant · Mar 18 – Apr 1
Onion setsPlant outdoors · Mar 11 – Mar 25
PotatoesPlant outdoors · Mar 18 – Apr 1
LettuceSow outdoors · Mar 11 – Mar 25
Carrots, beetsSow outdoors · Mar 18 – Apr 1
TomatoesStart indoors · Feb 11 – Feb 25
TomatoesTransplant · Apr 15 – Apr 29
Peppers, eggplantStart indoors · Jan 28 – Feb 11
Peppers, eggplantTransplant · Apr 22 – May 6
BeansSow outdoors · Apr 15 – Apr 29
Sweet cornSow outdoors · Apr 15 – Apr 29
Cucumbers, squashSow outdoors · Apr 15 – Apr 29
Fall lettuce, spinachSow outdoors · Sep 3 – Sep 17
GarlicPlant cloves · Oct 15 – Nov 19
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 8) and first fall frost (Oct 29) 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 61437 came on Mar 12 — 19 days earlier than the 1991–2020 average (Mar 31).

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 Gladstone, IL.

Soil in Gladstone, IL

The soil mapped at the center of ZIP 61437 is Cresent — loam, well drained.

TextureLoama good balance for most vegetables
pH6.5neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter3%moderate
Hydrologic groupBwater soaks in moderately
Farmland classprime farmlandUSDA classification

Map unit: Cresent loam, 2 to 5 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 61437; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Gladstone, IL

Summer high86 °Faverage high, July
Winter low16 °Faverage low, January
Hot days21days a year at 90 °F or more
Freezing nights122nights a year at 32 °F or less
Growing degree days3,578base 50 °F — the season’s usable heat
Longest day15 h 07 mindaylight on June 21
Shortest day9 h 14 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation37.2 inper year, rain and melted snow
Snowfall17 inper year

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 32 °F, low 16 °F 32°16° JanFebruary: average high 37 °F, low 20 °F 37°20° FebMarch: average high 49 °F, low 30 °F 49°30° MarApril: average high 62 °F, low 42 °F 62°42° AprMay: average high 73 °F, low 53 °F 73°53° MayJune: average high 82 °F, low 63 °F 82°63° JunJuly: average high 86 °F, low 67 °F 86°67° JulAugust: average high 84 °F, low 65 °F 84°65° AugSeptember: average high 78 °F, low 56 °F 78°56° SepOctober: average high 65 °F, low 45 °F 65°45° OctNovember: average high 50 °F, low 33 °F 50°33° NovDecember: average high 37 °F, low 22 °F 37°22° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″6″January: 1.39 in precipitation, 4.9 in snowfall 1.4❄5 JanFebruary: 1.69 in precipitation, 6.3 in snowfall 1.7❄6 FebMarch: 2.35 in precipitation, 1.8 in snowfall 2.4❄2 MarApril: 3.77 in precipitation, 0.3 in snowfall 3.8 AprMay: 5.02 in precipitation 5.0 MayJune: 4.66 in precipitation 4.7 JunJuly: 4.03 in precipitation 4.0 JulAugust: 3.60 in precipitation 3.6 AugSeptember: 3.62 in precipitation 3.6 SepOctober: 2.80 in precipitation, 0.1 in snowfall 2.8 OctNovember: 2.45 in precipitation, 0.3 in snowfall 2.5 NovDecember: 1.81 in precipitation, 3.2 in snowfall 1.8❄3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Gladstone Dam 18, IL (3 mi away); precipitation: Gladstone Dam 18, IL (3 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

614185b
Biggsville, IL · 6 mi
614256a
Carman, IL · 7 mi
526016a
Burlington, IA · 7 mi
614695b
Oquawka, IL · 9 mi
614806a
Stronghurst, IL · 9 mi
526506a
Sperry, IA · 11 mi
526556a
West Burlington, IA · 12 mi
614546a
Lomax, IL · 12 mi

Illinois planting zones →

Questions about 61437

What planting zone is ZIP code 61437?

ZIP code 61437 (Gladstone, 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 Gladstone, IL?

The median last spring frost (32 °F) near 61437 is April 8; after April 23 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Gladstone Dam 18 station.

When is the first frost in Gladstone, IL?

The median first fall frost near 61437 is October 29, giving a median frost-free growing season of 202 days.

When should I plant tomatoes in 61437?

Start tomato seeds indoors around Feb 11 – Feb 25 and set transplants outside around Apr 15 – Apr 29, one to three weeks after the median last frost.

How much rain and snow does 61437 get?

About 37.2 inches of precipitation a year and 17 inches of snowfall (NOAA 1991–2020 normals, Gladstone Dam 18 station).

How hot do summers get in Gladstone, IL?

The average high peaks at 86 °F in July, with about 21 days a year at 90 °F or more.

What kind of soil does 61437 have?

The USDA soil survey maps Cresent at the center of ZIP 61437: loam, well drained, pH about 6.5 (neutral).

Did spring come early in Gladstone, IL in 2026?

Spring leaf-out near 61437 came on Mar 12 in 2026, 19 days earlier than the 1991–2020 average (Mar 31), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Gladstone, IL?

Long-day onions: the longest day near 61437 is 15 h 07 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 61437 change?

Yes. The 2012 USDA map put 61437 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.