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

Planting zone for 37729 — Duff, TN

ZIP code 37729 (Duff, Campbell County) is in USDA zone 7b: the coldest winter night averages 5 to 10 °F. The median last spring frost is April 18 and the first fall frost October 24.

Where ZIP 37729 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 18
First frostOct 24
2012 zone6a

Was 6a on the 2012 map — 1.5 zones 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 Duff, 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 Duff, TN

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 18median — 50% chance of a later frost
Safe for tender plantsMay 3only 10% chance of frost after
First fall frostOctober 24median — 10% chance by Oct 11
Growing season187 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 3 and returns around November 1.

From the NOAA station Newcomb, TN — 8 miles away, elevation 1,014 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 37729

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 7 – Mar 21
SpinachSow outdoors · Mar 7 – Mar 28
Broccoli, cabbageStart indoors · Feb 7 – Feb 21
Broccoli, cabbageTransplant · Mar 28 – Apr 11
Onion setsPlant outdoors · Mar 21 – Apr 4
PotatoesPlant outdoors · Mar 28 – Apr 11
LettuceSow outdoors · Mar 21 – Apr 4
Carrots, beetsSow outdoors · Mar 28 – Apr 11
TomatoesStart indoors · Feb 21 – Mar 7
TomatoesTransplant · Apr 25 – May 9
Peppers, eggplantStart indoors · Feb 7 – Feb 21
Peppers, eggplantTransplant · May 2 – May 16
BeansSow outdoors · Apr 25 – May 9
Sweet cornSow outdoors · Apr 25 – May 9
Cucumbers, squashSow outdoors · Apr 25 – May 9
Fall lettuce, spinachSow outdoors · Aug 29 – Sep 12
GarlicPlant cloves · Oct 10 – Nov 14
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 18) and first fall frost (Oct 24) 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 37729 came on Feb 26 — 8 days earlier than the 1991–2020 average (Mar 6).

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 Duff, TN

The soil mapped at the center of ZIP 37729 is Muskingum — silt loam, well drained.

TextureSilt loama good balance for most vegetables
pH5.3strongly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2%moderate
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Muskingum-Sequoia-Petros complex, 30 to 60 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 37729; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Duff, TN

Summer high86 °Faverage high, July
Winter low26 °Faverage low, January
Hot days25days a year at 90 °F or more
Freezing nights107nights a year at 32 °F or less
Growing degree days3,831base 50 °F — the season’s usable heat
Longest day14 h 39 mindaylight on June 21
Shortest day9 h 40 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation54.6 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 46 °F, low 26 °F 46°26° JanFebruary: average high 50 °F, low 28 °F 50°28° FebMarch: average high 59 °F, low 34 °F 59°34° MarApril: average high 69 °F, low 42 °F 69°42° AprMay: average high 77 °F, low 52 °F 77°52° MayJune: average high 83 °F, low 60 °F 83°60° JunJuly: average high 86 °F, low 64 °F 86°64° JulAugust: average high 85 °F, low 63 °F 85°63° AugSeptember: average high 80 °F, low 57 °F 80°57° SepOctober: average high 70 °F, low 44 °F 70°44° OctNovember: average high 58 °F, low 33 °F 58°33° NovDecember: average high 49 °F, low 29 °F 49°29° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 4.61 in precipitation 4.6 JanFebruary: 5.00 in precipitation 5.0 FebMarch: 5.17 in precipitation 5.2 MarApril: 5.14 in precipitation 5.1 AprMay: 4.78 in precipitation 4.8 MayJune: 4.96 in precipitation 5.0 JunJuly: 5.75 in precipitation 5.8 JulAugust: 3.84 in precipitation 3.8 AugSeptember: 3.64 in precipitation 3.6 SepOctober: 2.77 in precipitation 2.8 OctNovember: 3.78 in precipitation 3.8 NovDecember: 5.12 in precipitation 5.1 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Newcomb, TN (8 mi away); precipitation: Newcomb, TN (8 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

377157a
Clairfield, TN · 5 mi
377307a
Eagan, TN · 5 mi
377627a
Jellico, TN · 6 mi
409407b
Frakes, KY · 8 mi
377667a
La Follette, TN · 8 mi
378197a
Newcomb, TN · 10 mi
378707a
Speedwell, TN · 12 mi
407637a
Siler, KY · 13 mi

Tennessee planting zones →

Questions about 37729

What planting zone is ZIP code 37729?

ZIP code 37729 (Duff, 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 Duff, TN?

The median last spring frost (32 °F) near 37729 is April 18; after May 3 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Newcomb station.

When is the first frost in Duff, TN?

The median first fall frost near 37729 is October 24, giving a median frost-free growing season of 187 days.

When should I plant tomatoes in 37729?

Start tomato seeds indoors around Feb 21 – Mar 7 and set transplants outside around Apr 25 – May 9, one to three weeks after the median last frost.

How much rain and snow does 37729 get?

About 54.6 inches of precipitation a year (NOAA 1991–2020 normals, Newcomb station).

How hot do summers get in Duff, TN?

The average high peaks at 86 °F in July, with about 25 days a year at 90 °F or more.

What kind of soil does 37729 have?

The USDA soil survey maps Muskingum at the center of ZIP 37729: silt loam, well drained, pH about 5.3 (strongly acidic).

Did spring come early in Duff, TN in 2026?

Spring leaf-out near 37729 came on Feb 26 in 2026, 8 days earlier than the 1991–2020 average (Mar 6), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Duff, TN?

Intermediate onions: the longest day near 37729 is 14 h 39 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 37729 change?

Yes. The 2012 USDA map put 37729 in zone 6a; the 2023 map puts it in zone 7b. The newer map uses 1991–2020 data and more weather stations.