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

Planting zone for 37820 — New Market, TN

ZIP code 37820 (New Market, Jefferson County) is in USDA zone 7b: the coldest winter night averages 5 to 10 °F. The median last spring frost is April 24 and the first fall frost October 17.

Where ZIP 37820 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 24

First frostOct 17

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 New Market, 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 New Market, TN

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 24median — 50% chance of a later frost

Safe for tender plantsMay 13only 10% chance of frost after

First fall frostOctober 17median — 10% chance by Oct 6

Growing season175 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 11 and returns around October 27.

From the NOAA station Jefferson City, TN — 6 miles away, elevation 1,109 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 37820

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 13 – Mar 27

SpinachSow outdoors · Mar 13 – Apr 3

Broccoli, cabbageStart indoors · Feb 13 – Feb 27

Broccoli, cabbageTransplant · Apr 3 – Apr 17

Onion setsPlant outdoors · Mar 27 – Apr 10

PotatoesPlant outdoors · Apr 3 – Apr 17

LettuceSow outdoors · Mar 27 – Apr 10

Carrots, beetsSow outdoors · Apr 3 – Apr 17

TomatoesStart indoors · Feb 27 – Mar 13

TomatoesTransplant · May 1 – May 15

Peppers, eggplantStart indoors · Feb 13 – Feb 27

Peppers, eggplantTransplant · May 8 – May 22

BeansSow outdoors · May 1 – May 15

Sweet cornSow outdoors · May 1 – May 15

Cucumbers, squashSow outdoors · May 1 – May 15

Fall lettuce, spinachSow outdoors · Aug 22 – Sep 5

GarlicPlant cloves · Oct 3 – Nov 7

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 24) and first fall frost (Oct 17) 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 37820 came on Feb 21 — 6 days earlier than the 1991–2020 average (Feb 27).

average
Feb 272026
Feb 21

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 7b in Tennessee

566 plants native to the lower 48 states, recorded in Tennessee, and rated by the USDA to survive 5 °F or colder — the bottom of zone 7b. 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 New Market, TN.

Soil in New Market, TN

The soil mapped at the center of ZIP 37820 is Fullerton — gravelly silt loam, well drained.

TextureGravelly silt loama good balance for most vegetables

pH5.5moderately 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: Fullerton 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 37820; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in New Market, TN

Summer high87 °Faverage high, July

Winter low25 °Faverage low, January

Hot days24days a year at 90 °F or more

Freezing nights103nights a year at 32 °F or less

Growing degree days3,763base 50 °F — the season’s usable heat

Longest day14 h 37 mindaylight on June 21

Shortest day9 h 42 mindaylight on December 21

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

Precipitation48.5 inper year, rain and melted snow

Snowfall3 inper year; 1 days with snow on the ground

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Jefferson City, TN (6 mi away); precipitation: Jefferson City, TN (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7b.

377607b

Jefferson City, TN · 6 mi

378717b

Strawberry Plains, TN · 7 mi

Dandridge, TN · 11 mi

Tennessee planting zones →

Questions about 37820

What planting zone is ZIP code 37820?

ZIP code 37820 (New Market, 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 New Market, TN?

The median last spring frost (32 °F) near 37820 is April 24; after May 13 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Jefferson City station.

When is the first frost in New Market, TN?

The median first fall frost near 37820 is October 17, giving a median frost-free growing season of 175 days.

When should I plant tomatoes in 37820?

Start tomato seeds indoors around Feb 27 – Mar 13 and set transplants outside around May 1 – May 15, one to three weeks after the median last frost.

How much rain and snow does 37820 get?

About 48.5 inches of precipitation a year and 3 inches of snowfall (NOAA 1991–2020 normals, Jefferson City station).

How hot do summers get in New Market, TN?

The average high peaks at 87 °F in July, with about 24 days a year at 90 °F or more.

What kind of soil does 37820 have?

The USDA soil survey maps Fullerton at the center of ZIP 37820: gravelly silt loam, well drained, pH about 5.5 (moderately acidic).

Did spring come early in New Market, TN in 2026?

Spring leaf-out near 37820 came on Feb 21 in 2026, 6 days earlier than the 1991–2020 average (Feb 27), according to the USA National Phenology Network Spring Index.

What kind of onions grow in New Market, TN?

Intermediate onions: the longest day near 37820 is 14 h 37 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 37820 change?

Yes. The 2012 USDA map put 37820 in zone 7a; the 2023 map puts it in zone 7b. The newer map uses 1991–2020 data and more weather stations.