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

Planting zone for 06070 — Simsbury, CT

ZIP code 06070 (Simsbury, Capitol Region County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 21 and the first fall frost October 16.

Where ZIP 06070 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 21

First frostOct 16

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 Simsbury, 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 Simsbury, CT

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 21median — 50% chance of a later frost

Safe for tender plantsMay 6only 10% chance of frost after

First fall frostOctober 16median — 10% chance by Oct 3

Growing season177 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 7 and returns around October 29.

From the NOAA station Hartford Bradley Intl Airport, CT — 8 miles away, elevation 190 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 06070

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 10 – Mar 24

SpinachSow outdoors · Mar 10 – Mar 31

Broccoli, cabbageStart indoors · Feb 10 – Feb 24

Broccoli, cabbageTransplant · Mar 31 – Apr 14

Onion setsPlant outdoors · Mar 24 – Apr 7

PotatoesPlant outdoors · Mar 31 – Apr 14

LettuceSow outdoors · Mar 24 – Apr 7

Carrots, beetsSow outdoors · Mar 31 – Apr 14

TomatoesStart indoors · Feb 24 – Mar 10

TomatoesTransplant · Apr 28 – May 12

Peppers, eggplantStart indoors · Feb 10 – Feb 24

Peppers, eggplantTransplant · May 5 – May 19

BeansSow outdoors · Apr 28 – May 12

Sweet cornSow outdoors · Apr 28 – May 12

Cucumbers, squashSow outdoors · Apr 28 – May 12

Fall lettuce, spinachSow outdoors · Aug 21 – Sep 4

GarlicPlant cloves · Oct 2 – Nov 6

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 21) and first fall frost (Oct 16) 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 06070 came on Apr 2 — 6 days earlier than the 1991–2020 average (Apr 8).

average
Apr 82026
Apr 2

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.

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 Simsbury, CT.

Soil in Simsbury, CT

The soil mapped at the center of ZIP 06070 is Merrimac — fine sandy loam, somewhat excessively drained.

TextureFine sandy loamdrains and warms fast; dries out and needs more feeding

pH5.1strongly acidic; most vegetables like 6.0–7.0

DrainageSomewhat excessively drainednatural drainage class

Organic matter4.12%moderate

Hydrologic groupAwater soaks in fast

Farmland classprime farmlandUSDA classification

Map unit: Merrimac fine sandy loam, 3 to 8 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 06070; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Simsbury, CT

Summer high85 °Faverage high, July

Winter low19 °Faverage low, January

Hot days20days a year at 90 °F or more

Freezing nights126nights a year at 32 °F or less

Growing degree days3,069base 50 °F — the season’s usable heat

Longest day15 h 14 mindaylight on June 21

Shortest day9 h 08 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation52.1 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Hartford Bradley Intl Airport, CT (8 mi away); precipitation: North Canton 0.8 Ssw, CT (4 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.

060926b

West Simsbury, CT · 2 mi

060896b

Weatogue, CT · 3 mi

060816b

Tariffville, CT · 3 mi

060596a

North Canton, CT · 4 mi

060026b

Bloomfield, CT · 4 mi

060196a

Canton, CT · 5 mi

060206a

Canton Center, CT · 5 mi

060266b

East Granby, CT · 5 mi

Connecticut planting zones →

Questions about 06070

What planting zone is ZIP code 06070?

ZIP code 06070 (Simsbury, 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 Simsbury, CT?

The median last spring frost (32 °F) near 06070 is April 21; after May 6 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Hartford Bradley Intl Airport station.

When is the first frost in Simsbury, CT?

The median first fall frost near 06070 is October 16, giving a median frost-free growing season of 177 days.

When should I plant tomatoes in 06070?

Start tomato seeds indoors around Feb 24 – Mar 10 and set transplants outside around Apr 28 – May 12, one to three weeks after the median last frost.

How much rain and snow does 06070 get?

About 52.1 inches of precipitation a year (NOAA 1991–2020 normals, North Canton 0.8 Ssw station).

How hot do summers get in Simsbury, CT?

The average high peaks at 85 °F in July, with about 20 days a year at 90 °F or more.

What kind of soil does 06070 have?

The USDA soil survey maps Merrimac at the center of ZIP 06070: fine sandy loam, somewhat excessively drained, pH about 5.1 (strongly acidic).

Did spring come early in Simsbury, CT in 2026?

Spring leaf-out near 06070 came on Apr 2 in 2026, 6 days earlier than the 1991–2020 average (Apr 8), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Simsbury, CT?

Long-day onions: the longest day near 06070 is 15 h 14 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 06070 change?

Yes. The 2012 USDA map put 06070 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.