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

Planting zone for 07945 — Mendham, NJ

ZIP code 07945 (Mendham, Morris County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 26 and the first fall frost October 18.

Where ZIP 07945 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 26

First frostOct 18

2012 zone6b

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 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Mendham, 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 Mendham, NJ

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 26median — 50% chance of a later frost

Safe for tender plantsMay 13only 10% chance of frost after

First fall frostOctober 18median — 10% chance by Oct 5

Growing season176 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 11 and returns around October 30.

From the NOAA station Somerville Somerset Airport, NJ — 11 miles away, elevation 105 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 07945

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 15 – Mar 29

SpinachSow outdoors · Mar 15 – Apr 5

Broccoli, cabbageStart indoors · Feb 15 – Mar 1

Broccoli, cabbageTransplant · Apr 5 – Apr 19

Onion setsPlant outdoors · Mar 29 – Apr 12

PotatoesPlant outdoors · Apr 5 – Apr 19

LettuceSow outdoors · Mar 29 – Apr 12

Carrots, beetsSow outdoors · Apr 5 – Apr 19

TomatoesStart indoors · Mar 1 – Mar 15

TomatoesTransplant · May 3 – May 17

Peppers, eggplantStart indoors · Feb 15 – Mar 1

Peppers, eggplantTransplant · May 10 – May 24

BeansSow outdoors · May 3 – May 17

Sweet cornSow outdoors · May 3 – May 17

Cucumbers, squashSow outdoors · May 3 – May 17

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 26) 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 07945 came on Mar 31 — 6 days earlier than the 1991–2020 average (Apr 6).

average
Apr 62026
Mar 31

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 New Jersey

581 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 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 Mendham, NJ.

Soil in Mendham, NJ

The soil mapped at the center of ZIP 07945 is Gladstone — gravelly loam, well drained. Much of the area is built over (urban land); this is the natural soil underneath.

TextureGravelly loama good balance for most vegetables

pH5.0strongly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter3%moderate

Hydrologic groupBwater soaks in moderately

Farmland classNot prime farmlandUSDA classification

Map unit: Urban land-Gladstone complex, 8 to 15 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 07945; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Mendham, NJ

Summer high86 °Faverage high, July

Winter low21 °Faverage low, January

Hot days23days a year at 90 °F or more

Freezing nights124nights a year at 32 °F or less

Growing degree days3,215base 50 °F — the season’s usable heat

Longest day15 h 06 mindaylight on June 21

Shortest day9 h 15 mindaylight on December 21

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

Precipitation48.9 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: Somerville Somerset Airport, NJ (11 mi away); precipitation: Mendham 1.5 W, NJ (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

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

079266b

Brookside, NJ · 2 mi

079706b

Mount Freedom, NJ · 3 mi

078456b

Ironia, NJ · 3 mi

079246b

Bernardsville, NJ · 4 mi

Morristown, NJ · 5 mi

New Jersey planting zones →

Questions about 07945

What planting zone is ZIP code 07945?

ZIP code 07945 (Mendham, NJ) 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 Mendham, NJ?

The median last spring frost (32 °F) near 07945 is April 26; after May 13 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Somerville Somerset Airport station.

When is the first frost in Mendham, NJ?

The median first fall frost near 07945 is October 18, giving a median frost-free growing season of 176 days.

When should I plant tomatoes in 07945?

Start tomato seeds indoors around Mar 1 – Mar 15 and set transplants outside around May 3 – May 17, one to three weeks after the median last frost.

How much rain and snow does 07945 get?

About 48.9 inches of precipitation a year (NOAA 1991–2020 normals, Mendham 1.5 W station).

How hot do summers get in Mendham, NJ?

The average high peaks at 86 °F in July, with about 23 days a year at 90 °F or more.

What kind of soil does 07945 have?

The USDA soil survey maps Gladstone at the center of ZIP 07945: gravelly loam, well drained, pH about 5.0 (strongly acidic).

Did spring come early in Mendham, NJ in 2026?

Spring leaf-out near 07945 came on Mar 31 in 2026, 6 days earlier than the 1991–2020 average (Apr 6), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Mendham, NJ?

Long-day onions: the longest day near 07945 is 15 h 06 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).