Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 62280 — Rockwood, IL

ZIP code 62280 (Rockwood, Randolph County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 19 and the first fall frost October 20.

Where ZIP 62280 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 19

First frostOct 20

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 Rockwood, 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 Rockwood, IL

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostApril 19median — 50% chance of a later frost

Safe for tender plantsMay 3only 10% chance of frost after

First fall frostOctober 20median — 10% chance by Oct 5

Growing season182 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 5 and returns around October 30.

From the NOAA station Perryville Wtp, MO — 17 miles away, elevation 502 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 62280

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 8 – Mar 22

SpinachSow outdoors · Mar 8 – Mar 29

Broccoli, cabbageStart indoors · Feb 8 – Feb 22

Broccoli, cabbageTransplant · Mar 29 – Apr 12

Onion setsPlant outdoors · Mar 22 – Apr 5

PotatoesPlant outdoors · Mar 29 – Apr 12

LettuceSow outdoors · Mar 22 – Apr 5

Carrots, beetsSow outdoors · Mar 29 – Apr 12

TomatoesStart indoors · Feb 22 – Mar 8

TomatoesTransplant · Apr 26 – May 10

Peppers, eggplantStart indoors · Feb 8 – Feb 22

Peppers, eggplantTransplant · May 3 – May 17

BeansSow outdoors · Apr 26 – May 10

Sweet cornSow outdoors · Apr 26 – May 10

Cucumbers, squashSow outdoors · Apr 26 – May 10

Fall lettuce, spinachSow outdoors · Aug 25 – Sep 8

GarlicPlant cloves · Oct 6 – Nov 10

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 19) and first fall frost (Oct 20) 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 62280 came on Mar 2 — 9 days earlier than the 1991–2020 average (Mar 11).

average
Mar 112026
Mar 2

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.

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 Rockwood, IL.

Soil in Rockwood, IL

The soil mapped at the center of ZIP 62280 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-Wellston silt loams, 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 62280; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Rockwood, IL

Summer high88 °Faverage high, July

Winter low21 °Faverage low, January

Hot days39days a year at 90 °F or more

Freezing nights114nights a year at 32 °F or less

Growing degree days3,938base 50 °F — the season’s usable heat

Longest day14 h 47 mindaylight on June 21

Shortest day9 h 32 mindaylight on December 21

Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully

Precipitation43.9 inper year, rain and melted snow

Snowfall12 inper year

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Perryville Wtp, MO (17 mi away); precipitation: Chester, IL (11 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

629167a

Campbell Hill, IL · 8 mi

Willisville, IL · 10 mi

622337a

Chester, IL · 10 mi

622887a

Steeleville, IL · 10 mi

622727a

Percy, IL · 10 mi

Illinois planting zones →

Questions about 62280

What planting zone is ZIP code 62280?

ZIP code 62280 (Rockwood, 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 Rockwood, IL?

The median last spring frost (32 °F) near 62280 is April 19; after May 3 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Perryville Wtp station.

When is the first frost in Rockwood, IL?

The median first fall frost near 62280 is October 20, giving a median frost-free growing season of 182 days.

When should I plant tomatoes in 62280?

Start tomato seeds indoors around Feb 22 – Mar 8 and set transplants outside around Apr 26 – May 10, one to three weeks after the median last frost.

How much rain and snow does 62280 get?

About 43.9 inches of precipitation a year and 12 inches of snowfall (NOAA 1991–2020 normals, Chester station).

How hot do summers get in Rockwood, IL?

The average high peaks at 88 °F in July, with about 39 days a year at 90 °F or more.

What kind of soil does 62280 have?

The USDA soil survey maps Menfro at the center of ZIP 62280: silt loam, well drained, pH about 6.2 (slightly acidic).

Did spring come early in Rockwood, IL in 2026?

Spring leaf-out near 62280 came on Mar 2 in 2026, 9 days earlier than the 1991–2020 average (Mar 11), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Rockwood, IL?

Intermediate onions: the longest day near 62280 is 14 h 47 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 62280 change?

Yes. The 2012 USDA map put 62280 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.