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

Planting zone for 37683 — Mountain City, TN

ZIP code 37683 (Mountain City, Johnson County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 27 and the first fall frost October 14.

Where ZIP 37683 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 27

First frostOct 14

2012 zone6a

Was 6a on the 2012 map — a full 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 Mountain City, 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 Mountain City, TN

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 27median — 50% chance of a later frost

Safe for tender plantsMay 15only 10% chance of frost after

First fall frostOctober 14median — 10% chance by Oct 3

Growing season170 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 12 and returns around October 24.

From the NOAA station Mtn City 2, TN — 2 miles away, elevation 2,418 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 37683

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 16 – Mar 30

SpinachSow outdoors · Mar 16 – Apr 6

Broccoli, cabbageStart indoors · Feb 16 – Mar 2

Broccoli, cabbageTransplant · Apr 6 – Apr 20

Onion setsPlant outdoors · Mar 30 – Apr 13

PotatoesPlant outdoors · Apr 6 – Apr 20

LettuceSow outdoors · Mar 30 – Apr 13

Carrots, beetsSow outdoors · Apr 6 – Apr 20

TomatoesStart indoors · Mar 2 – Mar 16

TomatoesTransplant · May 4 – May 18

Peppers, eggplantStart indoors · Feb 16 – Mar 2

Peppers, eggplantTransplant · May 11 – May 25

BeansSow outdoors · May 4 – May 18

Sweet cornSow outdoors · May 4 – May 18

Cucumbers, squashSow outdoors · May 4 – May 18

Fall lettuce, spinachSow outdoors · Aug 19 – Sep 2

GarlicPlant cloves · Sep 30 – Nov 4

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 27) and first fall frost (Oct 14) 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 37683 came on Mar 7 — 6 days earlier than the 1991–2020 average (Mar 13).

average
Mar 132026
Mar 7

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 Tennessee

560 plants native to the lower 48 states, recorded in Tennessee, 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 Mountain City, TN.

Soil in Mountain City, TN

The soil mapped at the center of ZIP 37683 is Ditney — sandy loam, well drained.

TextureSandy loamdrains and warms fast; dries out and needs more feeding

pH4.6strongly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter3%moderate

Hydrologic groupBwater soaks in moderately

Farmland classNot prime farmlandUSDA classification

Map unit: Ditney sandy loam, 35 to 50 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 37683; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Mountain City, TN

Summer high82 °Faverage high, July

Winter low23 °Faverage low, January

Hot days3days a year at 90 °F or more

Freezing nights126nights a year at 32 °F or less

Growing degree days3,119base 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

Precipitation47.2 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: Mtn City 2, TN (2 mi away); precipitation: Mtn City 2, TN (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

376917a

Trade, TN · 7 mi

376887a

Shady Valley, TN · 7 mi

Laurel Bloomery, TN · 10 mi

286987a

Zionville, NC · 10 mi

376407a

Butler, TN · 12 mi

286797a

Sugar Grove, NC · 13 mi

Tennessee planting zones →

Questions about 37683

What planting zone is ZIP code 37683?

ZIP code 37683 (Mountain City, TN) 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 Mountain City, TN?

The median last spring frost (32 °F) near 37683 is April 27; after May 15 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Mtn City 2 station.

When is the first frost in Mountain City, TN?

The median first fall frost near 37683 is October 14, giving a median frost-free growing season of 170 days.

When should I plant tomatoes in 37683?

Start tomato seeds indoors around Mar 2 – Mar 16 and set transplants outside around May 4 – May 18, one to three weeks after the median last frost.

How much rain and snow does 37683 get?

About 47.2 inches of precipitation a year and 12 inches of snowfall (NOAA 1991–2020 normals, Mtn City 2 station).

How hot do summers get in Mountain City, TN?

The average high peaks at 82 °F in July, with about 3 days a year at 90 °F or more.

What kind of soil does 37683 have?

The USDA soil survey maps Ditney at the center of ZIP 37683: sandy loam, well drained, pH about 4.6 (strongly acidic).

Did spring come early in Mountain City, TN in 2026?

Spring leaf-out near 37683 came on Mar 7 in 2026, 6 days earlier than the 1991–2020 average (Mar 13), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Mountain City, TN?

Intermediate onions: the longest day near 37683 is 14 h 39 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 37683 change?

Yes. The 2012 USDA map put 37683 in zone 6a; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.