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

Planting zone for 02455 — North Waltham, MA

ZIP code 02455 (North Waltham, Middlesex County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 19 and the first fall frost October 23.

Where ZIP 02455 is

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 19
First frostOct 23
2012 zone6a

Was 6a 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 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for North Waltham, MA…

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 North Waltham, MA

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 3only 10% chance of frost after
First fall frostOctober 23median — 10% chance by Oct 8
Growing season185 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 5 and returns around November 3.

From the NOAA station Jamaica Plain, MA — 6 miles away, elevation 95 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 02455

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 · 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 19) 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 02455 came on Apr 3 — 5 days earlier than the 1991–2020 average (Apr 8).

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 Massachusetts

548 plants native to the lower 48 states, recorded in Massachusetts, and rated by the USDA to survive −5 °F or colder — the bottom of zone 6b. Each links to its USDA PLANTS profile.

Trees 66

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 109

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 188

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 159

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 °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 8

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °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 °Ftrumpet creeper2 ft · blooms summer · high shade tolerance · to −13 °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 North Waltham, MA.

Soil in North Waltham, MA

The soil mapped at the center of ZIP 02455 is Merrimac — fine sandy loam, somewhat excessively drained.

TextureFine sandy loamdrains and warms fast; dries out and needs more feeding
pH5.1strongly acidic; most vegetables like 6.0–7.0
DrainageSomewhat excessively drainednatural drainage class
Organic matter4.12%moderate
Hydrologic groupAwater soaks in fast
Farmland classNot prime farmlandUSDA classification

Map unit: Merrimac-Urban land complex, 0 to 8 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 02455; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in North Waltham, MA

Summer high85 °Faverage high, July
Winter low19 °Faverage low, January
Hot days20days a year at 90 °F or more
Freezing nights121nights a year at 32 °F or less
Growing degree days3,047base 50 °F — the season’s usable heat
Longest day15 h 17 mindaylight on June 21
Shortest day9 h 04 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation49.3 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 37 °F, low 19 °F 37°19° JanFebruary: average high 40 °F, low 21 °F 40°21° FebMarch: average high 47 °F, low 28 °F 47°28° MarApril: average high 59 °F, low 38 °F 59°38° AprMay: average high 69 °F, low 48 °F 69°48° MayJune: average high 79 °F, low 58 °F 79°58° JunJuly: average high 85 °F, low 64 °F 85°64° JulAugust: average high 83 °F, low 63 °F 83°63° AugSeptember: average high 76 °F, low 55 °F 76°55° SepOctober: average high 64 °F, low 43 °F 64°43° OctNovember: average high 53 °F, low 34 °F 53°34° NovDecember: average high 42 °F, low 26 °F 42°26° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 3.72 in precipitation 3.7 JanFebruary: 3.74 in precipitation 3.7 FebMarch: 4.52 in precipitation 4.5 MarApril: 4.37 in precipitation 4.4 AprMay: 3.66 in precipitation 3.7 MayJune: 4.38 in precipitation 4.4 JunJuly: 3.46 in precipitation 3.5 JulAugust: 3.72 in precipitation 3.7 AugSeptember: 3.92 in precipitation 3.9 SepOctober: 4.78 in precipitation 4.8 OctNovember: 4.05 in precipitation 4.0 NovDecember: 4.97 in precipitation 5.0 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Jamaica Plain, MA (6 mi away); precipitation: Cambridge 0.9 Nnw, MA (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6b.

024956b
Nonantum, MA · <1 mi
024606b
Newtonville, MA · <1 mi
024586b
Newton, MA · 1 mi
024716b
Watertown, MA · 1 mi
024776b
Watertown, MA · 1 mi
024656b
West Newton, MA · 1 mi
024726b
Watertown, MA · 1 mi
024536b
Waltham, MA · 2 mi

Massachusetts planting zones →

Questions about 02455

What planting zone is ZIP code 02455?

ZIP code 02455 (North Waltham, MA) 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 North Waltham, MA?

The median last spring frost (32 °F) near 02455 is April 19; after May 3 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Jamaica Plain station.

When is the first frost in North Waltham, MA?

The median first fall frost near 02455 is October 23, giving a median frost-free growing season of 185 days.

When should I plant tomatoes in 02455?

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 02455 get?

About 49.3 inches of precipitation a year (NOAA 1991–2020 normals, Cambridge 0.9 Nnw station).

How hot do summers get in North Waltham, MA?

The average high peaks at 85 °F in July, with about 20 days a year at 90 °F or more.

What kind of soil does 02455 have?

The USDA soil survey maps Merrimac at the center of ZIP 02455: fine sandy loam, somewhat excessively drained, pH about 5.1 (strongly acidic).

Did spring come early in North Waltham, MA in 2026?

Spring leaf-out near 02455 came on Apr 3 in 2026, 5 days earlier than the 1991–2020 average (Apr 8), according to the USA National Phenology Network Spring Index.

What kind of onions grow in North Waltham, MA?

Long-day onions: the longest day near 02455 is 15 h 17 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 02455 change?

Yes. The 2012 USDA map put 02455 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.