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

Planting zone for 11970 — South Jamesport, NY

ZIP code 11970 (South Jamesport, Suffolk County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 19 and the first fall frost November 1.

Where ZIP 11970 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 19
First frostNov 1
2012 zone7a

Same zone as on the 2012 map. 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 South Jamesport, NY…

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 South Jamesport, NY

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 19median — 50% chance of a later frost
Safe for tender plantsMay 4only 10% chance of frost after
First fall frostNovember 1median — 10% chance by Oct 17
Growing season196 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 4 and returns around November 12.

From the NOAA station Mattituck, NY — 4 miles away, elevation 20 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 11970

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 8 – Mar 22
SpinachSow outdoors · Mar 8 – Mar 29
Broccoli, cabbageStart indoors · Feb 8 – Feb 22
Broccoli, cabbageTransplant · Mar 29 – Apr 12
Onion setsPlant outdoors · Mar 22 – Apr 5
PotatoesPlant outdoors · Mar 29 – Apr 12
LettuceSow outdoors · Mar 22 – Apr 5
Carrots, beetsSow outdoors · Mar 29 – Apr 12
TomatoesStart indoors · Feb 22 – Mar 8
TomatoesTransplant · Apr 26 – May 10
Peppers, eggplantStart indoors · Feb 8 – Feb 22
Peppers, eggplantTransplant · May 3 – May 17
BeansSow outdoors · Apr 26 – May 10
Sweet cornSow outdoors · Apr 26 – May 10
Cucumbers, squashSow outdoors · Apr 26 – May 10
Fall lettuce, spinachSow outdoors · Sep 6 – Sep 20
GarlicPlant cloves · Oct 18 – Nov 22
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 19) and first fall frost (Nov 1) 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 11970 came on Apr 3 — about the same time as the 1991–2020 average (Apr 3).

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 New York

656 plants native to the lower 48 states, recorded in New York, and rated by the USDA to survive 0 °F or colder — the bottom of zone 7a. Each links to its USDA PLANTS profile.

Trees 78

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 131

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 221

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 200

alkali sacaton3 ft · blooms mid summer · high shade tolerance · to −38 °FAmerican 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 °F

Vines 9

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °FAmerican wisteria50 ft · blooms 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 °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 South Jamesport, NY.

Soil in South Jamesport, NY

The center of ZIP 11970 is mapped as Fill land, dredged material: 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 11970; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in South Jamesport, NY

Summer high82 °Faverage high, July
Winter low23 °Faverage low, January
Hot days7days a year at 90 °F or more
Freezing nights105nights a year at 32 °F or less
Growing degree days2,921base 50 °F — the season’s usable heat
Longest day15 h 07 mindaylight on June 21
Shortest day9 h 14 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation45 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 38 °F, low 23 °F 38°23° JanFebruary: average high 40 °F, low 24 °F 40°24° FebMarch: average high 47 °F, low 30 °F 47°30° MarApril: average high 57 °F, low 39 °F 57°39° AprMay: average high 67 °F, low 48 °F 67°48° MayJune: average high 75 °F, low 59 °F 75°59° JunJuly: average high 82 °F, low 65 °F 82°65° JulAugust: average high 81 °F, low 64 °F 81°64° AugSeptember: average high 74 °F, low 57 °F 74°57° SepOctober: average high 64 °F, low 46 °F 64°46° OctNovember: average high 53 °F, low 36 °F 53°36° NovDecember: average high 43 °F, low 28 °F 43°28° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 3.61 in precipitation 3.6 JanFebruary: 3.12 in precipitation 3.1 FebMarch: 4.25 in precipitation 4.3 MarApril: 4.06 in precipitation 4.1 AprMay: 3.45 in precipitation 3.5 MayJune: 3.75 in precipitation 3.8 JunJuly: 3.08 in precipitation 3.1 JulAugust: 4.12 in precipitation 4.1 AugSeptember: 3.79 in precipitation 3.8 SepOctober: 4.04 in precipitation 4.0 OctNovember: 3.50 in precipitation 3.5 NovDecember: 4.26 in precipitation 4.3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Mattituck, NY (4 mi away); precipitation: Mattituck, NY (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

119487a
Laurel, NY · 2 mi
119317a
Aquebogue, NY · 3 mi
119017a
Riverhead, NY · 4 mi
119527a
Mattituck, NY · 4 mi
119467a
Hampton Bays, NY · 6 mi
119567a
New Suffolk, NY · 6 mi
119427a
East Quogue, NY · 6 mi
119357a
Cutchogue, NY · 7 mi

New York planting zones →

Questions about 11970

What planting zone is ZIP code 11970?

ZIP code 11970 (South Jamesport, NY) 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 South Jamesport, NY?

The median last spring frost (32 °F) near 11970 is April 19; after May 4 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Mattituck station.

When is the first frost in South Jamesport, NY?

The median first fall frost near 11970 is November 1, giving a median frost-free growing season of 196 days.

When should I plant tomatoes in 11970?

Start tomato seeds indoors around Feb 22 – Mar 8 and set transplants outside around Apr 26 – May 10, one to three weeks after the median last frost.

How much rain and snow does 11970 get?

About 45 inches of precipitation a year (NOAA 1991–2020 normals, Mattituck station).

How hot do summers get in South Jamesport, NY?

The average high peaks at 82 °F in July, with about 7 days a year at 90 °F or more.

Did spring come early in South Jamesport, NY in 2026?

Spring leaf-out near 11970 came on Apr 3 in 2026, about the same as the 1991–2020 average (Apr 3), according to the USA National Phenology Network Spring Index.

What kind of onions grow in South Jamesport, NY?

Long-day onions: the longest day near 11970 is 15 h 07 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).