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

Planting zone for 37621 — Bristol, TN

ZIP code 37621 (Bristol, Sullivan County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 16 and the first fall frost October 24.

Where ZIP 37621 is

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 16
First frostOct 24
2012 zone6b

Was 6b 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 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Bristol, 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 Bristol, TN

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 16median — 50% chance of a later frost
Safe for tender plantsMay 5only 10% chance of frost after
First fall frostOctober 24median — 10% chance by Oct 11
Growing season190 daysfrost-free, median

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

From the NOAA station Bristol Tri City Airport, TN — 8 miles away, elevation 1,499 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 37621

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 5 – Mar 19
SpinachSow outdoors · Mar 5 – Mar 26
Broccoli, cabbageStart indoors · Feb 5 – Feb 19
Broccoli, cabbageTransplant · Mar 26 – Apr 9
Onion setsPlant outdoors · Mar 19 – Apr 2
PotatoesPlant outdoors · Mar 26 – Apr 9
LettuceSow outdoors · Mar 19 – Apr 2
Carrots, beetsSow outdoors · Mar 26 – Apr 9
TomatoesStart indoors · Feb 19 – Mar 5
TomatoesTransplant · Apr 23 – May 7
Peppers, eggplantStart indoors · Feb 5 – Feb 19
Peppers, eggplantTransplant · Apr 30 – May 14
BeansSow outdoors · Apr 23 – May 7
Sweet cornSow outdoors · Apr 23 – May 7
Cucumbers, squashSow outdoors · Apr 23 – May 7
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 16) 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 37621 came on Mar 1 — about the same time as the 1991–2020 average (Mar 1).

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.

Trees 80

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 °Farborvitae50 ft · blooms mid spring · medium shade tolerance · to −33 °F

Shrubs 116

alderleaf buckthorn3 ft · blooms late spring · low shade tolerance · to −33 °FAllegheny serviceberry35 ft · blooms early spring · low shade tolerance · to −38 °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 182

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 speedwell0.8 ft · blooms mid summer · low shade tolerance · to −38 °FAmerican spongeplant0.5 ft · blooms mid spring · high shade tolerance · to −24 °F

Grasses 155

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 °FBailey's sedge2.1 ft · blooms late spring · low shade tolerance · to −33 °Fbig bluestem6 ft · blooms summer · high shade tolerance · to −46 °Fbluejoint5 ft · blooms late spring · high shade tolerance · to −33 °F

Vines 14

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 Bristol, TN.

Soil in Bristol, TN

The center of ZIP 37621 is mapped as Urban land-Udorthents complex: built-over ground without natural soil data. Garden soil here is usually imported or disturbed — test before you plant.

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 37621; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Bristol, TN

Summer high86 °Faverage high, July
Winter low26 °Faverage low, January
Hot days23days a year at 90 °F or more
Freezing nights94nights a year at 32 °F or less
Growing degree days3,903base 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
Precipitation44 inper year, rain and melted snow
Snowfall9 inper year; 7 days with snow on the ground

Average high and low, by month

20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 47 °F, low 26 °F 47°26° JanFebruary: average high 51 °F, low 29 °F 51°29° FebMarch: average high 59 °F, low 35 °F 59°35° MarApril: average high 69 °F, low 43 °F 69°43° AprMay: average high 77 °F, low 52 °F 77°52° MayJune: average high 84 °F, low 61 °F 84°61° JunJuly: average high 86 °F, low 65 °F 86°65° JulAugust: average high 86 °F, low 63 °F 86°63° AugSeptember: average high 81 °F, low 56 °F 81°56° SepOctober: average high 70 °F, low 44 °F 70°44° OctNovember: average high 59 °F, low 34 °F 59°34° NovDecember: average high 50 °F, low 29 °F 50°29° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″January: 3.65 in precipitation, 3 in snowfall 3.6❄3 JanFebruary: 3.81 in precipitation, 3 in snowfall 3.8❄3 FebMarch: 3.96 in precipitation, 1.1 in snowfall 4.0❄1 MarApril: 3.79 in precipitation, 0.1 in snowfall 3.8 AprMay: 3.82 in precipitation 3.8 MayJune: 3.92 in precipitation 3.9 JunJuly: 5.00 in precipitation 5.0 JulAugust: 3.76 in precipitation 3.8 AugSeptember: 2.84 in precipitation 2.8 SepOctober: 2.52 in precipitation 2.5 OctNovember: 3.14 in precipitation, 0.3 in snowfall 3.1 NovDecember: 3.76 in precipitation, 1.7 in snowfall 3.8❄2 Dec

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

Nearby ZIP codes

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

376187b
Bluff City, TN · 4 mi
376177b
Blountville, TN · 6 mi
376997b
Piney Flats, TN · 6 mi
376867b
Piney Flats, TN · 6 mi
376257b
Bristol, TN · 8 mi
242037a
Bristol, VA · 8 mi
242097a
Bristol, VA · 8 mi
242057a
Bristol, VA · 8 mi

All 3 ZIP codes in Bristol → · Tennessee planting zones →

Questions about 37621

What planting zone is ZIP code 37621?

ZIP code 37621 (Bristol, 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 Bristol, TN?

The median last spring frost (32 °F) near 37621 is April 16; after May 5 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Bristol Tri City Airport station.

When is the first frost in Bristol, TN?

The median first fall frost near 37621 is October 24, giving a median frost-free growing season of 190 days.

When should I plant tomatoes in 37621?

Start tomato seeds indoors around Feb 19 – Mar 5 and set transplants outside around Apr 23 – May 7, one to three weeks after the median last frost.

How much rain and snow does 37621 get?

About 44 inches of precipitation a year and 9 inches of snowfall (NOAA 1991–2020 normals, Bristol Tri City Airport station).

How hot do summers get in Bristol, TN?

The average high peaks at 86 °F in July, with about 23 days a year at 90 °F or more.

Did spring come early in Bristol, TN in 2026?

Spring leaf-out near 37621 came on Mar 1 in 2026, about the same as the 1991–2020 average (Mar 1), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Bristol, TN?

Intermediate onions: the longest day near 37621 is 14 h 39 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 37621 change?

Yes. The 2012 USDA map put 37621 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.