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

Planting zone for 08618 — Trenton, NJ

ZIP code 08618 (Trenton, Mercer County) is in USDA zone 7b: the coldest winter night averages 5 to 10 °F. The median last spring frost is April 17 and the first fall frost October 28.

Where ZIP 08618 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.

Zone7b5 to 10 °F

Coldest night−15 to −12.2 °C

Last frostApr 17

First frostOct 28

2012 zone7a

Was 7a 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 7b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Trenton, NJ…

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 Trenton, NJ

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 6only 10% chance of frost after

First fall frostOctober 28median — 10% chance by Oct 11

Growing season192 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 2 and returns around November 7.

From the NOAA station Trenton State College, NJ — within 1 mile, elevation 102 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 08618

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 2 – Sep 16

GarlicPlant cloves · Oct 14 – Nov 18

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 17) and first fall frost (Oct 28) 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 08618 came on Mar 22 — about the same time as the 1991–2020 average (Mar 23).

average
Mar 232026
Mar 22

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 7b in New Jersey

605 plants native to the lower 48 states, recorded in New Jersey, and rated by the USDA to survive 5 °F or colder — the bottom of zone 7b. 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 Trenton, NJ.

Soil in Trenton, NJ

The soil mapped at the center of ZIP 08618 is Mattapex — loam, moderately well drained.

TextureLoama good balance for most vegetables

pH4.6strongly acidic; most vegetables like 6.0–7.0

DrainageModerately well drainednatural drainage class

Organic matter1.75%low — add compost

Hydrologic groupCwater soaks in slowly

Farmland classFarmland of statewide importanceUSDA classification

Map unit: Mattapex and Bertie loams, 0 to 5 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 08618; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Trenton, NJ

Summer high87 °Faverage high, July

Winter low23 °Faverage low, January

Hot days24days a year at 90 °F or more

Freezing nights109nights a year at 32 °F or less

Growing degree days3,400base 50 °F — the season’s usable heat

Longest day15 h 03 mindaylight on June 21

Shortest day9 h 18 mindaylight on December 21

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

Precipitation48.6 inper year, rain and melted snow

Snowfall27 inper year

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Trenton State College, NJ (within 1 mile); precipitation: Ewing Twp 0.8 Ese, NJ (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

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

Morrisville, PA · 4 mi

086487a

Lawrence Township, NJ · 5 mi

All 25 ZIP codes in Trenton → · New Jersey planting zones →

Questions about 08618

What planting zone is ZIP code 08618?

ZIP code 08618 (Trenton, NJ) is in USDA hardiness zone 7b on the 2023 map: the coldest night of an average winter reaches 5 to 10 °F (−15 to −12.2 °C).

When is the last frost in Trenton, NJ?

The median last spring frost (32 °F) near 08618 is April 17; after May 6 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Trenton State College station.

When is the first frost in Trenton, NJ?

The median first fall frost near 08618 is October 28, giving a median frost-free growing season of 192 days.

When should I plant tomatoes in 08618?

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 08618 get?

About 48.6 inches of precipitation a year and 27 inches of snowfall (NOAA 1991–2020 normals, Ewing Twp 0.8 Ese station).

How hot do summers get in Trenton, NJ?

The average high peaks at 87 °F in July, with about 24 days a year at 90 °F or more.

What kind of soil does 08618 have?

The USDA soil survey maps Mattapex at the center of ZIP 08618: loam, moderately well drained, pH about 4.6 (strongly acidic).

Did spring come early in Trenton, NJ in 2026?

Spring leaf-out near 08618 came on Mar 22 in 2026, about the same as the 1991–2020 average (Mar 23), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Trenton, NJ?

Long-day onions: the longest day near 08618 is 15 h 03 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 08618 change?

Yes. The 2012 USDA map put 08618 in zone 7a; the 2023 map puts it in zone 7b. The newer map uses 1991–2020 data and more weather stations.