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

Planting zone for 01886 — Westford, MA

ZIP code 01886 (Westford, Middlesex County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is April 30 and the first fall frost October 10.

Where ZIP 01886 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.

Zone6a−10 to −5 °F
Coldest night−23.3 to −20.6 °C
Last frostApr 30
First frostOct 10
2012 zone6a

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 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Westford, 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 Westford, MA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 30median — 50% chance of a later frost
Safe for tender plantsMay 10only 10% chance of frost after
First fall frostOctober 10median — 10% chance by Sep 30
Growing season164 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 18 and returns around October 22.

From the NOAA station Lowell, MA — 6 miles away, elevation 112 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 01886

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 19 – Apr 2
SpinachSow outdoors · Mar 19 – Apr 9
Broccoli, cabbageStart indoors · Feb 19 – Mar 5
Broccoli, cabbageTransplant · Apr 9 – Apr 23
Onion setsPlant outdoors · Apr 2 – Apr 16
PotatoesPlant outdoors · Apr 9 – Apr 23
LettuceSow outdoors · Apr 2 – Apr 16
Carrots, beetsSow outdoors · Apr 9 – Apr 23
TomatoesStart indoors · Mar 5 – Mar 19
TomatoesTransplant · May 7 – May 21
Peppers, eggplantStart indoors · Feb 19 – Mar 5
Peppers, eggplantTransplant · May 14 – May 28
BeansSow outdoors · May 7 – May 21
Sweet cornSow outdoors · May 7 – May 21
Cucumbers, squashSow outdoors · May 7 – May 21
Fall lettuce, spinachSow outdoors · Aug 15 – Aug 29
GarlicPlant cloves · Sep 26 – Oct 31
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 30) and first fall frost (Oct 10) 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 01886 came on Apr 9 — about the same time as the 1991–2020 average (Apr 10).

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 6a in Massachusetts

544 plants native to the lower 48 states, recorded in Massachusetts, and rated by the USDA to survive −10 °F or colder — the bottom of zone 6a. 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 186

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 157

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 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °FBailey's sedge2.1 ft · blooms late spring · low shade tolerance · to −33 °Fbeaked spikerush3 ft · blooms late spring · high shade tolerance · to −28 °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 Westford, MA.

Soil in Westford, MA

The soil mapped at the center of ZIP 01886 is Montauk — moderately decomposed plant material, well drained.

TextureModerately decomposed plant materialtop layer
DrainageWell drainednatural drainage class
Organic matter95%high
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Montauk fine sandy loam, 15 to 35 percent slopes, extremely stony.

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 01886; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Westford, MA

Summer high85 °Faverage high, July
Winter low16 °Faverage low, January
Hot days20days a year at 90 °F or more
Freezing nights148nights a year at 32 °F or less
Growing degree days2,736base 50 °F — the season’s usable heat
Longest day15 h 19 mindaylight on June 21
Shortest day9 h 03 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation48.5 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 34 °F, low 16 °F 34°16° JanFebruary: average high 37 °F, low 17 °F 37°17° FebMarch: average high 45 °F, low 24 °F 45°24° MarApril: average high 59 °F, low 35 °F 59°35° AprMay: average high 70 °F, low 45 °F 70°45° MayJune: average high 79 °F, low 55 °F 79°55° JunJuly: average high 85 °F, low 61 °F 85°61° JulAugust: average high 83 °F, low 59 °F 83°59° AugSeptember: average high 76 °F, low 52 °F 76°52° SepOctober: average high 62 °F, low 40 °F 62°40° OctNovember: average high 51 °F, low 30 °F 51°30° NovDecember: average high 40 °F, low 22 °F 40°22° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 3.61 in precipitation 3.6 JanFebruary: 3.20 in precipitation 3.2 FebMarch: 4.32 in precipitation 4.3 MarApril: 4.06 in precipitation 4.1 AprMay: 3.81 in precipitation 3.8 MayJune: 4.37 in precipitation 4.4 JunJuly: 3.86 in precipitation 3.9 JulAugust: 4.00 in precipitation 4.0 AugSeptember: 3.89 in precipitation 3.9 SepOctober: 5.00 in precipitation 5.0 OctNovember: 3.85 in precipitation 3.9 NovDecember: 4.54 in precipitation 4.5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Lowell, MA (6 mi away); precipitation: Lowell, MA (6 mi away). 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.

018636b
North Chelmsford, MA · 4 mi
014606a
Littleton, MA · 4 mi
018246b
Chelmsford, MA · 4 mi
017416b
Carlisle, MA · 5 mi
018796a
Tyngsboro, MA · 6 mi
018516b
Lowell, MA · 6 mi
018546b
Lowell, MA · 6 mi
014506a
Groton, MA · 7 mi

Massachusetts planting zones →

Questions about 01886

What planting zone is ZIP code 01886?

ZIP code 01886 (Westford, MA) is in USDA hardiness zone 6a on the 2023 map: the coldest night of an average winter reaches −10 to −5 °F (−23.3 to −20.6 °C).

When is the last frost in Westford, MA?

The median last spring frost (32 °F) near 01886 is April 30; after May 10 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Lowell station.

When is the first frost in Westford, MA?

The median first fall frost near 01886 is October 10, giving a median frost-free growing season of 164 days.

When should I plant tomatoes in 01886?

Start tomato seeds indoors around Mar 5 – Mar 19 and set transplants outside around May 7 – May 21, one to three weeks after the median last frost.

How much rain and snow does 01886 get?

About 48.5 inches of precipitation a year (NOAA 1991–2020 normals, Lowell station).

How hot do summers get in Westford, 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 01886 have?

The USDA soil survey maps Montauk at the center of ZIP 01886: moderately decomposed plant material, well drained.

Did spring come early in Westford, MA in 2026?

Spring leaf-out near 01886 came on Apr 9 in 2026, about the same as the 1991–2020 average (Apr 10), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Westford, MA?

Long-day onions: the longest day near 01886 is 15 h 19 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).