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

Planting zone for 06443 — Madison, CT

ZIP code 06443 (Madison, South Central Regional County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 17 and the first fall frost October 27.

Where ZIP 06443 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 17

First frostOct 27

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 Madison, 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 Madison, CT

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 17median — 50% chance of a later frost

Safe for tender plantsMay 1only 10% chance of frost after

First fall frostOctober 27median — 10% chance by Oct 11

Growing season193 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 4 and returns around November 6.

From the NOAA station New Haven Tweed Airport, CT — 15 miles away, elevation 3 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 06443

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 6 – Mar 20

SpinachSow outdoors · Mar 6 – Mar 27

Broccoli, cabbageStart indoors · Feb 6 – Feb 20

Broccoli, cabbageTransplant · Mar 27 – Apr 10

Onion setsPlant outdoors · Mar 20 – Apr 3

PotatoesPlant outdoors · Mar 27 – Apr 10

LettuceSow outdoors · Mar 20 – Apr 3

Carrots, beetsSow outdoors · Mar 27 – Apr 10

TomatoesStart indoors · Feb 20 – Mar 6

TomatoesTransplant · Apr 24 – May 8

Peppers, eggplantStart indoors · Feb 6 – Feb 20

Peppers, eggplantTransplant · May 1 – May 15

BeansSow outdoors · Apr 24 – May 8

Sweet cornSow outdoors · Apr 24 – May 8

Cucumbers, squashSow outdoors · Apr 24 – May 8

Fall lettuce, spinachSow outdoors · Sep 1 – Sep 15

GarlicPlant cloves · Oct 13 – Nov 17

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 17) and first fall frost (Oct 27) 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 06443 came on Apr 2 — about the same time as the 1991–2020 average (Apr 4).

average
Apr 42026
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 7a in Connecticut

546 plants native to the lower 48 states, recorded in Connecticut, 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 Madison, CT.

Soil in Madison, CT

The soil mapped at the center of ZIP 06443 is Canton — slightly decomposed plant material, well drained.

TextureSlightly decomposed plant materialtop layer

DrainageWell drainednatural drainage class

Organic matter95%high

Hydrologic groupBwater soaks in moderately

Farmland classNot prime farmlandUSDA classification

Map unit: Canton and Charlton fine sandy loams, 3 to 15 percent slopes, extremely stony.

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 06443; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Madison, CT

Summer high82 °Faverage high, July

Winter low23 °Faverage low, January

Hot days6days a year at 90 °F or more

Freezing nights102nights a year at 32 °F or less

Growing degree days3,028base 50 °F — the season’s usable heat

Longest day15 h 10 mindaylight on June 21

Shortest day9 h 11 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

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: New Haven Tweed Airport, CT (15 mi away); precipitation: Killingworth 2.6 Ese, CT (6 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.

064196b

Killingworth, CT · 3 mi

North Branford, CT · 8 mi

064177a

Deep River, CT · 8 mi

Connecticut planting zones →

Questions about 06443

What planting zone is ZIP code 06443?

ZIP code 06443 (Madison, CT) 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 Madison, CT?

The median last spring frost (32 °F) near 06443 is April 17; after May 1 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, New Haven Tweed Airport station.

When is the first frost in Madison, CT?

The median first fall frost near 06443 is October 27, giving a median frost-free growing season of 193 days.

When should I plant tomatoes in 06443?

Start tomato seeds indoors around Feb 20 – Mar 6 and set transplants outside around Apr 24 – May 8, one to three weeks after the median last frost.

How much rain and snow does 06443 get?

About 52 inches of precipitation a year (NOAA 1991–2020 normals, Killingworth 2.6 Ese station).

How hot do summers get in Madison, CT?

The average high peaks at 82 °F in July, with about 6 days a year at 90 °F or more.

What kind of soil does 06443 have?

The USDA soil survey maps Canton at the center of ZIP 06443: slightly decomposed plant material, well drained.

Did spring come early in Madison, CT in 2026?

Spring leaf-out near 06443 came on Apr 2 in 2026, about the same as the 1991–2020 average (Apr 4), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Madison, CT?

Long-day onions: the longest day near 06443 is 15 h 10 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 06443 change?

Yes. The 2012 USDA map put 06443 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.