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

Planting zone for 38581 — Rock Island, TN

ZIP code 38581 (Rock Island, Warren County) is in USDA zone 7b: the coldest winter night averages 5 to 10 °F. The median last spring frost is April 6 and the first fall frost October 30.

Where ZIP 38581 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.

Zone7b5 to 10 °F
Coldest night−15 to −12.2 °C
Last frostApr 6
First frostOct 30
2012 zone7a

Was 7a 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 7b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Rock Island, TN…

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 Rock Island, TN

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 6median — 50% chance of a later frost
Safe for tender plantsApril 22only 10% chance of frost after
First fall frostOctober 30median — 10% chance by Oct 17
Growing season207 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 26 and returns around November 9.

From the NOAA station Rock Island Sp, TN — 5 miles away, elevation 879 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 38581

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 23 – Mar 9
SpinachSow outdoors · Feb 23 – Mar 16
Broccoli, cabbageStart indoors · Jan 26 – Feb 9
Broccoli, cabbageTransplant · Mar 16 – Mar 30
Onion setsPlant outdoors · Mar 9 – Mar 23
PotatoesPlant outdoors · Mar 16 – Mar 30
LettuceSow outdoors · Mar 9 – Mar 23
Carrots, beetsSow outdoors · Mar 16 – Mar 30
TomatoesStart indoors · Feb 9 – Feb 23
TomatoesTransplant · Apr 13 – Apr 27
Peppers, eggplantStart indoors · Jan 26 – Feb 9
Peppers, eggplantTransplant · Apr 20 – May 4
BeansSow outdoors · Apr 13 – Apr 27
Sweet cornSow outdoors · Apr 13 – Apr 27
Cucumbers, squashSow outdoors · Apr 13 – Apr 27
Fall lettuce, spinachSow outdoors · Sep 4 – Sep 18
GarlicPlant cloves · Oct 16 – Nov 20
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 6) and first fall frost (Oct 30) 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 38581 came on Feb 21 — about the same time as the 1991–2020 average (Feb 23).

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).

Soil in Rock Island, TN

The soil mapped at the center of ZIP 38581 is Algood — gravelly silt loam, well drained.

TextureGravelly silt loama good balance for most vegetables
pH6.5neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter3%moderate
Hydrologic groupAwater soaks in fast
Farmland classNot prime farmlandUSDA classification

Map unit: Algood gravelly silt loam, 5 to 12 percent slopes, 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 38581; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Rock Island, TN

Summer high87 °Faverage high, July
Winter low29 °Faverage low, January
Hot days27days a year at 90 °F or more
Freezing nights74nights a year at 32 °F or less
Growing degree days4,459base 50 °F — the season’s usable heat
Longest day14 h 35 mindaylight on June 21
Shortest day9 h 44 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation59.4 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 48 °F, low 29 °F 48°29° JanFebruary: average high 53 °F, low 32 °F 53°32° FebMarch: average high 62 °F, low 39 °F 62°39° MarApril: average high 70 °F, low 47 °F 70°47° AprMay: average high 78 °F, low 56 °F 78°56° MayJune: average high 84 °F, low 64 °F 84°64° JunJuly: average high 87 °F, low 68 °F 87°68° JulAugust: average high 86 °F, low 67 °F 86°67° AugSeptember: average high 80 °F, low 61 °F 80°61° SepOctober: average high 71 °F, low 48 °F 71°48° OctNovember: average high 61 °F, low 38 °F 61°38° NovDecember: average high 52 °F, low 32 °F 52°32° Dec

Precipitation by month inches

0″2″4″6″January: 5.09 in precipitation 5.1 JanFebruary: 5.11 in precipitation 5.1 FebMarch: 6.02 in precipitation 6.0 MarApril: 5.16 in precipitation 5.2 AprMay: 4.78 in precipitation 4.8 MayJune: 5.37 in precipitation 5.4 JunJuly: 5.29 in precipitation 5.3 JulAugust: 4.29 in precipitation 4.3 AugSeptember: 4.04 in precipitation 4.0 SepOctober: 3.46 in precipitation 3.5 OctNovember: 4.56 in precipitation 4.6 NovDecember: 6.24 in precipitation 6.2 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Rock Island Sp, TN (5 mi away); precipitation: Rock Island Sp, TN (5 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

385507b
Campaign, TN · 2 mi
385797b
Quebeck, TN · 8 mi
385597b
Doyle, TN · 8 mi
385877b
Walling, TN · 9 mi
371117b
Mcminnville, TN · 9 mi
371107b
Mcminnville, TN · 9 mi
385857a
Spencer, TN · 12 mi
373787b
Smartt, TN · 14 mi

Tennessee planting zones →

Questions about 38581

What planting zone is ZIP code 38581?

ZIP code 38581 (Rock Island, TN) is in USDA hardiness zone 7b on the 2023 map: the coldest night of an average winter reaches 5 to 10 °F (−15 to −12.2 °C).

When is the last frost in Rock Island, TN?

The median last spring frost (32 °F) near 38581 is April 6; after April 22 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Rock Island Sp station.

When is the first frost in Rock Island, TN?

The median first fall frost near 38581 is October 30, giving a median frost-free growing season of 207 days.

When should I plant tomatoes in 38581?

Start tomato seeds indoors around Feb 9 – Feb 23 and set transplants outside around Apr 13 – Apr 27, one to three weeks after the median last frost.

How much rain and snow does 38581 get?

About 59.4 inches of precipitation a year (NOAA 1991–2020 normals, Rock Island Sp station).

How hot do summers get in Rock Island, TN?

The average high peaks at 87 °F in July, with about 27 days a year at 90 °F or more.

What kind of soil does 38581 have?

The USDA soil survey maps Algood at the center of ZIP 38581: gravelly silt loam, well drained, pH about 6.5 (neutral).

Did spring come early in Rock Island, TN in 2026?

Spring leaf-out near 38581 came on Feb 21 in 2026, about the same as the 1991–2020 average (Feb 23), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Rock Island, TN?

Intermediate onions: the longest day near 38581 is 14 h 35 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 38581 change?

Yes. The 2012 USDA map put 38581 in zone 7a; the 2023 map puts it in zone 7b. The newer map uses 1991–2020 data and more weather stations.