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

Planting zone for 06786 — Terryville, CT

ZIP code 06786 (Terryville, Naugatuck Valley County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 25 and the first fall frost October 18.

Where ZIP 06786 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.

Zone6b−5 to 0 °F
Coldest night−20.6 to −17.8 °C
Last frostApr 25
First frostOct 18
2012 zone6a

Was 6a 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 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Terryville, CT…

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 Terryville, CT

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 25median — 50% chance of a later frost
Safe for tender plantsMay 10only 10% chance of frost after
First fall frostOctober 18median — 10% chance by Oct 4
Growing season172 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 13 and returns around October 30.

From the NOAA station Burlington, CT — 9 miles away, elevation 505 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 06786

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 14 – Mar 28
SpinachSow outdoors · Mar 14 – Apr 4
Broccoli, cabbageStart indoors · Feb 14 – Feb 28
Broccoli, cabbageTransplant · Apr 4 – Apr 18
Onion setsPlant outdoors · Mar 28 – Apr 11
PotatoesPlant outdoors · Apr 4 – Apr 18
LettuceSow outdoors · Mar 28 – Apr 11
Carrots, beetsSow outdoors · Apr 4 – Apr 18
TomatoesStart indoors · Feb 28 – Mar 14
TomatoesTransplant · May 2 – May 16
Peppers, eggplantStart indoors · Feb 14 – Feb 28
Peppers, eggplantTransplant · May 9 – May 23
BeansSow outdoors · May 2 – May 16
Sweet cornSow outdoors · May 2 – May 16
Cucumbers, squashSow outdoors · May 2 – May 16
Fall lettuce, spinachSow outdoors · Aug 23 – Sep 6
GarlicPlant cloves · Oct 4 – Nov 8
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 25) and first fall frost (Oct 18) 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 06786 came on Apr 3 — 7 days earlier than the 1991–2020 average (Apr 10).

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 6b in Connecticut

533 plants native to the lower 48 states, recorded in Connecticut, and rated by the USDA to survive −5 °F or colder — the bottom of zone 6b. Each links to its USDA PLANTS profile.

Trees 64

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 105

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 black currant3 ft · blooms early spring · to −46 °FAmerican hazelnut10 ft · blooms spring · medium shade tolerance · to −33 °FAmerican holly40 ft · blooms mid spring · low shade tolerance · to −20 °F

Wildflowers & perennials 187

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °FAmerican bur-reed3 ft · blooms indeterminate · medium shade tolerance · to −33 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °FAmerican licorice4 ft · blooms late spring · medium shade tolerance · to −38 °FAmerican lotus3 ft · blooms mid summer · high shade tolerance · to −36 °FAmerican pokeweed7 ft · blooms mid summer · low shade tolerance · to −33 °F

Grasses 151

American beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °Farctic brome3 ft · blooms early summer · low shade tolerance · to −33 °FAtlantic mannagrass3 ft · blooms summer · low 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 °Fbeaked spikerush3 ft · blooms late spring · high shade tolerance · to −28 °F

Vines 9

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °Fcatbird grape30 ft · blooms late spring · medium shade tolerance · to −13 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °Fheartleaf peppervine2 ft · blooms late spring · low shade tolerance · to −8 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Fsummer grape30 ft · blooms late spring · low 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 Terryville, CT.

Soil in Terryville, CT

The soil mapped at the center of ZIP 06786 is Charlton — fine sandy loam, well drained.

TextureFine sandy loamdrains and warms fast; dries out and needs more feeding
pH5.5moderately acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter3.5%moderate
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Charlton-Chatfield complex, 15 to 45 percent slopes, very rocky.

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 06786; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Terryville, CT

Summer high84 °Faverage high, July
Winter low17 °Faverage low, January
Hot days13days a year at 90 °F or more
Freezing nights142nights a year at 32 °F or less
Growing degree days2,830base 50 °F — the season’s usable heat
Longest day15 h 12 mindaylight on June 21
Shortest day9 h 09 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation52 inper year, rain and melted snow

Average high and low, by month

10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 36 °F, low 17 °F 36°17° JanFebruary: average high 39 °F, low 18 °F 39°18° FebMarch: average high 47 °F, low 26 °F 47°26° MarApril: average high 60 °F, low 36 °F 60°36° AprMay: average high 70 °F, low 47 °F 70°47° MayJune: average high 79 °F, low 57 °F 79°57° JunJuly: average high 84 °F, low 62 °F 84°62° JulAugust: average high 82 °F, low 60 °F 82°60° AugSeptember: average high 75 °F, low 53 °F 75°53° SepOctober: average high 63 °F, low 41 °F 63°41° OctNovember: average high 52 °F, low 32 °F 52°32° NovDecember: average high 41 °F, low 24 °F 41°24° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 3.43 in precipitation 3.4 JanFebruary: 3.21 in precipitation 3.2 FebMarch: 4.20 in precipitation 4.2 MarApril: 4.51 in precipitation 4.5 AprMay: 4.29 in precipitation 4.3 MayJune: 4.47 in precipitation 4.5 JunJuly: 4.72 in precipitation 4.7 JulAugust: 4.39 in precipitation 4.4 AugSeptember: 4.60 in precipitation 4.6 SepOctober: 5.38 in precipitation 5.4 OctNovember: 4.02 in precipitation 4.0 NovDecember: 4.74 in precipitation 4.7 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Burlington, CT (9 mi away); precipitation: Thomaston Dam, CT (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

067816b
Pequabuck, CT · 1 mi
067826a
Plymouth, CT · 2 mi
067876a
Thomaston, CT · 3 mi
060116b
Bristol, CT · 4 mi
060106b
Bristol, CT · 4 mi
067786a
Northfield, CT · 5 mi
067046b
Waterbury, CT · 6 mi
067166b
Wolcott, CT · 6 mi

Connecticut planting zones →

Questions about 06786

What planting zone is ZIP code 06786?

ZIP code 06786 (Terryville, CT) is in USDA hardiness zone 6b on the 2023 map: the coldest night of an average winter reaches −5 to 0 °F (−20.6 to −17.8 °C).

When is the last frost in Terryville, CT?

The median last spring frost (32 °F) near 06786 is April 25; after May 10 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Burlington station.

When is the first frost in Terryville, CT?

The median first fall frost near 06786 is October 18, giving a median frost-free growing season of 172 days.

When should I plant tomatoes in 06786?

Start tomato seeds indoors around Feb 28 – Mar 14 and set transplants outside around May 2 – May 16, one to three weeks after the median last frost.

How much rain and snow does 06786 get?

About 52 inches of precipitation a year (NOAA 1991–2020 normals, Thomaston Dam station).

How hot do summers get in Terryville, CT?

The average high peaks at 84 °F in July, with about 13 days a year at 90 °F or more.

What kind of soil does 06786 have?

The USDA soil survey maps Charlton at the center of ZIP 06786: fine sandy loam, well drained, pH about 5.5 (moderately acidic).

Did spring come early in Terryville, CT in 2026?

Spring leaf-out near 06786 came on Apr 3 in 2026, 7 days earlier than the 1991–2020 average (Apr 10), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Terryville, CT?

Long-day onions: the longest day near 06786 is 15 h 12 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 06786 change?

Yes. The 2012 USDA map put 06786 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.