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

Planting zone for 62905 — Alto Pass, IL

ZIP code 62905 (Alto Pass, Union County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 8 and the first fall frost October 29.

Where ZIP 62905 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 8
First frostOct 29
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 Alto Pass, 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 Alto Pass, 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 26only 10% chance of frost after
First fall frostOctober 29median — 10% chance by Oct 17
Growing season203 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 29 and returns around November 8.

From the NOAA station Anna 2 Nne, IL — 9 miles away, elevation 640 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 62905

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 62905 came on Mar 1 — 8 days earlier than the 1991–2020 average (Mar 9).

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 Alto Pass, IL.

Soil in Alto Pass, IL

The soil mapped at the center of ZIP 62905 is Menfro — silt loam, well drained.

TextureSilt loama good balance for most vegetables
pH6.2slightly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter1.25%low — add compost
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Menfro-Clarksville complex, 18 to 35 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 62905; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Alto Pass, IL

Summer high90 °Faverage high, July
Winter low25 °Faverage low, January
Hot days43days a year at 90 °F or more
Freezing nights95nights a year at 32 °F or less
Growing degree days4,627base 50 °F — the season’s usable heat
Longest day14 h 46 mindaylight on June 21
Shortest day9 h 34 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation51.1 inper year, rain and melted snow
Snowfall10 inper year; 10 days with snow on the ground

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 45 °F, low 25 °F 45°25° JanFebruary: average high 50 °F, low 29 °F 50°29° FebMarch: average high 61 °F, low 37 °F 61°37° MarApril: average high 71 °F, low 46 °F 71°46° AprMay: average high 79 °F, low 56 °F 79°56° MayJune: average high 87 °F, low 65 °F 87°65° JunJuly: average high 90 °F, low 69 °F 90°69° JulAugust: average high 89 °F, low 67 °F 89°67° AugSeptember: average high 84 °F, low 59 °F 84°59° SepOctober: average high 73 °F, low 48 °F 73°48° OctNovember: average high 59 °F, low 37 °F 59°37° NovDecember: average high 48 °F, low 30 °F 48°30° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″6″January: 3.53 in precipitation, 2.6 in snowfall 3.5❄3 JanFebruary: 3.40 in precipitation, 4 in snowfall 3.4❄4 FebMarch: 4.82 in precipitation, 0.9 in snowfall 4.8❄1 MarApril: 5.63 in precipitation 5.6 AprMay: 5.93 in precipitation 5.9 MayJune: 4.95 in precipitation 5.0 JunJuly: 3.70 in precipitation 3.7 JulAugust: 3.15 in precipitation 3.1 AugSeptember: 3.49 in precipitation 3.5 SepOctober: 3.89 in precipitation, 0.2 in snowfall 3.9 OctNovember: 4.54 in precipitation, 0.1 in snowfall 4.5 NovDecember: 4.10 in precipitation, 2.6 in snowfall 4.1❄3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Anna 2 Nne, IL (9 mi away); precipitation: Anna 2 Nne, IL (9 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

629757a
Pomona, IL · 6 mi
629987a
Wolf Lake, IL · 6 mi
629207a
Cobden, IL · 7 mi
629427a
Grand Tower, IL · 8 mi
629037a
Carbondale, IL · 9 mi
629527a
Jonesboro, IL · 10 mi
637327a
Altenburg, MO · 12 mi
629067a
Anna, IL · 12 mi

Illinois planting zones →

Questions about 62905

What planting zone is ZIP code 62905?

ZIP code 62905 (Alto Pass, 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 Alto Pass, IL?

The median last spring frost (32 °F) near 62905 is April 8; after April 26 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Anna 2 Nne station.

When is the first frost in Alto Pass, IL?

The median first fall frost near 62905 is October 29, giving a median frost-free growing season of 203 days.

When should I plant tomatoes in 62905?

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 62905 get?

About 51.1 inches of precipitation a year and 10 inches of snowfall (NOAA 1991–2020 normals, Anna 2 Nne station).

How hot do summers get in Alto Pass, IL?

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

What kind of soil does 62905 have?

The USDA soil survey maps Menfro at the center of ZIP 62905: silt loam, well drained, pH about 6.2 (slightly acidic).

Did spring come early in Alto Pass, IL in 2026?

Spring leaf-out near 62905 came on Mar 1 in 2026, 8 days earlier than the 1991–2020 average (Mar 9), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Alto Pass, IL?

Intermediate onions: the longest day near 62905 is 14 h 46 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 62905 change?

Yes. The 2012 USDA map put 62905 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.