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

Planting zone for 07046 — Mountain Lakes, NJ

ZIP code 07046 (Mountain Lakes, Morris County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 17 and the first fall frost October 23.

Where ZIP 07046 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 17
First frostOct 23
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 Mountain Lakes, 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 Mountain Lakes, 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 5only 10% chance of frost after
First fall frostOctober 23median — 10% chance by Oct 8
Growing season189 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 4 and returns around November 2.

From the NOAA station Boonton 1 Se, NJ — 2 miles away, elevation 279 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 07046

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 · Aug 28 – Sep 11
GarlicPlant cloves · Oct 9 – Nov 13
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 17) and first fall frost (Oct 23) 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 07046 came on Mar 31 — 3 days earlier than 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 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.

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 116

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 197

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 lotus3 ft · blooms mid summer · high shade tolerance · to −36 °FAmerican pokeweed7 ft · blooms mid summer · low shade tolerance · to −33 °FAmerican speedwell0.8 ft · blooms mid summer · low shade tolerance · to −38 °F

Grasses 166

American beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °FAmerican cupscale3 ft · blooms early summer · high shade tolerance · to −18 °Farctic brome3 ft · blooms early summer · low shade tolerance · to −33 °FAtlantic mannagrass3 ft · blooms summer · low shade tolerance · to −8 °Fautumn bluegrass1.5 ft · blooms late spring · medium shade tolerance · to −8 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °F

Vines 9

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °Fcatbird grape30 ft · blooms late spring · medium shade tolerance · to −13 °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 Mountain Lakes, NJ.

Soil in Mountain Lakes, NJ

The soil mapped at the center of ZIP 07046 is Rockaway — sandy loam, well drained. Much of the area is built over (urban land); this is the natural soil underneath.

TextureSandy loamdrains and warms fast; dries out and needs more feeding
pH5.0strongly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2%moderate
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Urban land-Rockaway complex, 3 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 07046; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Mountain Lakes, NJ

Summer high85 °Faverage high, July
Winter low21 °Faverage low, January
Hot days16days a year at 90 °F or more
Freezing nights124nights a year at 32 °F or less
Growing degree days3,151base 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)
Precipitation49.5 inper year, rain and melted snow

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 38 °F, low 21 °F 38°21° JanFebruary: average high 40 °F, low 22 °F 40°22° FebMarch: average high 48 °F, low 29 °F 48°29° MarApril: average high 61 °F, low 39 °F 61°39° AprMay: average high 71 °F, low 49 °F 71°49° MayJune: average high 81 °F, low 59 °F 81°59° JunJuly: average high 85 °F, low 64 °F 85°64° JulAugust: average high 84 °F, low 62 °F 84°62° AugSeptember: average high 77 °F, low 54 °F 77°54° SepOctober: average high 64 °F, low 42 °F 64°42° OctNovember: average high 53 °F, low 33 °F 53°33° NovDecember: average high 42 °F, low 26 °F 42°26° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 3.73 in precipitation 3.7 JanFebruary: 3.06 in precipitation 3.1 FebMarch: 4.12 in precipitation 4.1 MarApril: 3.90 in precipitation 3.9 AprMay: 3.99 in precipitation 4.0 MayJune: 4.73 in precipitation 4.7 JunJuly: 4.60 in precipitation 4.6 JulAugust: 4.38 in precipitation 4.4 AugSeptember: 4.27 in precipitation 4.3 SepOctober: 4.55 in precipitation 4.5 OctNovember: 3.76 in precipitation 3.8 NovDecember: 4.46 in precipitation 4.5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Boonton 1 Se, NJ (2 mi away); precipitation: Denville Twp 1.5 Ese, NJ (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

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

078346b
Denville, NJ · 2 mi
070056b
Boonton, NJ · 3 mi
070547a
Parsippany, NJ · 3 mi
070347a
Lake Hiawatha, NJ · 3 mi
079506b
Morris Plains, NJ · 4 mi
070457a
Montville, NJ · 4 mi
079817a
Whippany, NJ · 5 mi
079277a
Cedar Knolls, NJ · 5 mi

New Jersey planting zones →

Questions about 07046

What planting zone is ZIP code 07046?

ZIP code 07046 (Mountain Lakes, 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 Mountain Lakes, NJ?

The median last spring frost (32 °F) near 07046 is April 17; after May 5 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Boonton 1 Se station.

When is the first frost in Mountain Lakes, NJ?

The median first fall frost near 07046 is October 23, giving a median frost-free growing season of 189 days.

When should I plant tomatoes in 07046?

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 07046 get?

About 49.5 inches of precipitation a year (NOAA 1991–2020 normals, Denville Twp 1.5 Ese station).

How hot do summers get in Mountain Lakes, NJ?

The average high peaks at 85 °F in July, with about 16 days a year at 90 °F or more.

What kind of soil does 07046 have?

The USDA soil survey maps Rockaway at the center of ZIP 07046: sandy loam, well drained, pH about 5.0 (strongly acidic).

Did spring come early in Mountain Lakes, NJ in 2026?

Spring leaf-out near 07046 came on Mar 31 in 2026, 3 days earlier than the 1991–2020 average (Apr 3), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Mountain Lakes, NJ?

Long-day onions: the longest day near 07046 is 15 h 07 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).