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

Planting zone for 35603 — Decatur, AL

ZIP code 35603 (Decatur, Morgan County) is in USDA zone 8a: the coldest winter night averages 10 to 15 °F. The median last spring frost is March 26 and the first fall frost November 7.

Where ZIP 35603 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.

Zone8a10 to 15 °F
Coldest night−12.2 to −9.4 °C
Last frostMar 26
First frostNov 7
2012 zone7b

Was 7b 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 8a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Decatur, AL…

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 Decatur, AL

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMarch 26median — 50% chance of a later frost
Safe for tender plantsApril 9only 10% chance of frost after
First fall frostNovember 7median — 10% chance by Oct 26
Growing season228 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 12 and returns around November 19.

From the NOAA station Decatur 4se, AL — 4 miles away, elevation 551 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 35603

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 12 – Feb 26
SpinachSow outdoors · Feb 12 – Mar 5
Broccoli, cabbageStart indoors · Jan 15 – Jan 29
Broccoli, cabbageTransplant · Mar 5 – Mar 19
Onion setsPlant outdoors · Feb 26 – Mar 12
PotatoesPlant outdoors · Mar 5 – Mar 19
LettuceSow outdoors · Feb 26 – Mar 12
Carrots, beetsSow outdoors · Mar 5 – Mar 19
TomatoesStart indoors · Jan 29 – Feb 12
TomatoesTransplant · Apr 2 – Apr 16
Peppers, eggplantStart indoors · Jan 15 – Jan 29
Peppers, eggplantTransplant · Apr 9 – Apr 23
BeansSow outdoors · Apr 2 – Apr 16
Sweet cornSow outdoors · Apr 2 – Apr 16
Cucumbers, squashSow outdoors · Apr 2 – Apr 16
Fall lettuce, spinachSow outdoors · Sep 12 – Sep 26
GarlicPlant cloves · Oct 24 – Nov 28
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 26) and first fall frost (Nov 7) 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 35603 came on Feb 14 — about the same time as the 1991–2020 average (Feb 15).

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 8a in Alabama

550 plants native to the lower 48 states, recorded in Alabama, and rated by the USDA to survive 10 °F or colder — the bottom of zone 8a. Each links to its USDA PLANTS profile.

Trees 83

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 °FAtlantic white cedar50 ft · blooms spring · medium shade tolerance · to −36 °F

Shrubs 125

Allegheny serviceberry35 ft · blooms early spring · low shade tolerance · to −38 °Faloe yucca15 ft · blooms early summer · medium shade tolerance · to −1 °Falternateleaf dogwood25 ft · blooms mid spring · low shade tolerance · to −47 °FAmerican beautyberry6 ft · blooms early summer · medium shade tolerance · to −8 °FAmerican hazelnut10 ft · blooms spring · medium shade tolerance · to −33 °FAmerican holly40 ft · blooms mid spring · low shade tolerance · to −20 °F

Wildflowers & perennials 171

American bur-reed3 ft · blooms indeterminate · medium shade tolerance · to −33 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °FAmerican lotus3 ft · blooms mid summer · high shade tolerance · to −36 °FAmerican pokeweed7 ft · blooms mid summer · low shade tolerance · to −33 °FAmerican spongeplant0.5 ft · blooms mid spring · high shade tolerance · to −24 °FAmerican water horehound1.8 ft · blooms early summer · low shade tolerance · to −38 °F

Grasses 148

American cupscale3 ft · blooms early summer · high shade tolerance · to −18 °Fautumn bluegrass1.5 ft · blooms late spring · medium shade tolerance · to −8 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °Fbeaked spikerush3 ft · blooms late spring · high shade tolerance · to −28 °Fbig bluestem6 ft · blooms summer · high shade tolerance · to −46 °Fbig cordgrass8 ft · blooms spring · high shade tolerance · to −3 °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 Decatur, AL.

Soil in Decatur, AL

The soil mapped at the center of ZIP 35603 is Sequatchie — fine sandy loam, well drained.

TextureFine sandy loamdrains and warms fast; dries out and needs more feeding
pH5.0strongly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2%moderate
Hydrologic groupBwater soaks in moderately
Farmland classprime farmlandUSDA classification

Map unit: Sequatchie fine sandy loam, eroded.

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 35603; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Decatur, AL

Summer high89 °Faverage high, July
Winter low31 °Faverage low, January
Hot days41days a year at 90 °F or more
Freezing nights52nights a year at 32 °F or less
Growing degree days5,071base 50 °F — the season’s usable heat
Longest day14 h 28 mindaylight on June 21
Shortest day9 h 50 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation58 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 52 °F, low 31 °F 52°31° JanFebruary: average high 57 °F, low 34 °F 57°34° FebMarch: average high 65 °F, low 41 °F 65°41° MarApril: average high 74 °F, low 49 °F 74°49° AprMay: average high 80 °F, low 58 °F 80°58° MayJune: average high 87 °F, low 66 °F 87°66° JunJuly: average high 89 °F, low 69 °F 89°69° JulAugust: average high 89 °F, low 68 °F 89°68° AugSeptember: average high 84 °F, low 62 °F 84°62° SepOctober: average high 74 °F, low 50 °F 74°50° OctNovember: average high 63 °F, low 40 °F 63°40° NovDecember: average high 55 °F, low 34 °F 55°34° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 5.44 in precipitation 5.4 JanFebruary: 5.56 in precipitation 5.6 FebMarch: 5.40 in precipitation 5.4 MarApril: 5.22 in precipitation 5.2 AprMay: 4.86 in precipitation 4.9 MayJune: 4.55 in precipitation 4.5 JunJuly: 4.84 in precipitation 4.8 JulAugust: 3.88 in precipitation 3.9 AugSeptember: 3.91 in precipitation 3.9 SepOctober: 3.92 in precipitation 3.9 OctNovember: 4.42 in precipitation 4.4 NovDecember: 5.97 in precipitation 6.0 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Decatur 4se, AL (4 mi away); precipitation: Decatur 4se, AL (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 8a.

356028a
Decatur, AL · 5 mi
356098a
Decatur, AL · 5 mi
356998a
Decatur, AL · 5 mi
356018a
Decatur, AL · 5 mi
356408a
Hartselle, AL · 7 mi
356498a
Mooresville, AL · 8 mi
356718a
Tanner, AL · 9 mi
356738a
Trinity, AL · 10 mi

All 5 ZIP codes in Decatur → · Alabama planting zones →

Questions about 35603

What planting zone is ZIP code 35603?

ZIP code 35603 (Decatur, AL) is in USDA hardiness zone 8a on the 2023 map: the coldest night of an average winter reaches 10 to 15 °F (−12.2 to −9.4 °C).

When is the last frost in Decatur, AL?

The median last spring frost (32 °F) near 35603 is March 26; after April 9 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Decatur 4se station.

When is the first frost in Decatur, AL?

The median first fall frost near 35603 is November 7, giving a median frost-free growing season of 228 days.

When should I plant tomatoes in 35603?

Start tomato seeds indoors around Jan 29 – Feb 12 and set transplants outside around Apr 2 – Apr 16, one to three weeks after the median last frost.

How much rain and snow does 35603 get?

About 58 inches of precipitation a year (NOAA 1991–2020 normals, Decatur 4se station).

How hot do summers get in Decatur, AL?

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 35603 have?

The USDA soil survey maps Sequatchie at the center of ZIP 35603: fine sandy loam, well drained, pH about 5.0 (strongly acidic).

Did spring come early in Decatur, AL in 2026?

Spring leaf-out near 35603 came on Feb 14 in 2026, about the same as the 1991–2020 average (Feb 15), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Decatur, AL?

Intermediate onions: the longest day near 35603 is 14 h 28 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 35603 change?

Yes. The 2012 USDA map put 35603 in zone 7b; the 2023 map puts it in zone 8a. The newer map uses 1991–2020 data and more weather stations.