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

Planting zone for Westminster, MA

Westminster, MA is in USDA zone 6a across its 2 ZIP codes. The median last spring frost is May 2 and the first fall frost October 13.

Westminster on the zone map

Outlined: its 1 ZIP code areas · 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
ZIP codes2
Last frostMay 2
First frostOct 13
Growing season163 days

6a 2 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Westminster, 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 Westminster, MA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 2median — 50% chance of a later frost
Safe for tender plantsMay 16only 10% chance of frost after
First fall frostOctober 13median — 10% chance by Oct 1
Growing season163 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 18 and returns around October 25.

From the NOAA station Ashburnham, MA, elevation 1,109 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 Westminster

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 21 – Apr 4
SpinachSow outdoors · Mar 21 – Apr 11
Broccoli, cabbageStart indoors · Feb 21 – Mar 7
Broccoli, cabbageTransplant · Apr 11 – Apr 25
Onion setsPlant outdoors · Apr 4 – Apr 18
PotatoesPlant outdoors · Apr 11 – Apr 25
LettuceSow outdoors · Apr 4 – Apr 18
Carrots, beetsSow outdoors · Apr 11 – Apr 25
TomatoesStart indoors · Mar 7 – Mar 21
TomatoesTransplant · May 9 – May 23
Peppers, eggplantStart indoors · Feb 21 – Mar 7
Peppers, eggplantTransplant · May 16 – May 30
BeansSow outdoors · May 9 – May 23
Sweet cornSow outdoors · May 9 – May 23
Cucumbers, squashSow outdoors · May 9 – May 23
Fall lettuce, spinachSow outdoors · Aug 18 – Sep 1
GarlicPlant cloves · Sep 29 – Nov 3
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 2) and first fall frost (Oct 13) 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 01473 came on Apr 12 — 5 days earlier than the 1991–2020 average (Apr 17).

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 Westminster, MA.

Soil in Westminster, MA

The soil mapped at the center of ZIP 01473 is Berkshire — slightly decomposed plant material, well drained.

TextureSlightly decomposed plant materialtop layer
pH3.5strongly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter85%high
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Berkshire-Marlow association, 15 to 45 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 01473; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Westminster, MA

Summer high80 °Faverage high, July
Winter low14 °Faverage low, January
Hot days3days a year at 90 °F or more
Freezing nights152nights a year at 32 °F or less
Growing degree days2,244base 50 °F — the season’s usable heat
Longest day15 h 18 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)
Precipitation49.1 inper year, rain and melted snow

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 31 °F, low 14 °F 31°14° JanFebruary: average high 33 °F, low 15 °F 33°15° FebMarch: average high 41 °F, low 23 °F 41°23° MarApril: average high 55 °F, low 34 °F 55°34° AprMay: average high 66 °F, low 44 °F 66°44° MayJune: average high 75 °F, low 54 °F 75°54° JunJuly: average high 80 °F, low 60 °F 80°60° JulAugust: average high 78 °F, low 57 °F 78°57° AugSeptember: average high 71 °F, low 51 °F 71°51° SepOctober: average high 57 °F, low 39 °F 57°39° OctNovember: average high 46 °F, low 31 °F 46°31° NovDecember: average high 35 °F, low 20 °F 35°20° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 3.47 in precipitation 3.5 JanFebruary: 3.13 in precipitation 3.1 FebMarch: 4.04 in precipitation 4.0 MarApril: 4.09 in precipitation 4.1 AprMay: 4.04 in precipitation 4.0 MayJune: 4.41 in precipitation 4.4 JunJuly: 3.74 in precipitation 3.7 JulAugust: 4.59 in precipitation 4.6 AugSeptember: 4.29 in precipitation 4.3 SepOctober: 5.04 in precipitation 5.0 OctNovember: 3.78 in precipitation 3.8 NovDecember: 4.48 in precipitation 4.5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Ashburnham, MA (4 mi away); precipitation: Westminster 0.6 Wsw, MA (within 1 mile). Daylight is calculated from latitude.

ZIP codes in Westminster

014416a
−10 to −5 °F
014736a
−10 to −5 °F

Massachusetts planting zones →

Questions about Westminster

What planting zone is Westminster, MA?

Westminster, MA is in USDA hardiness zone 6a on the 2023 map (6a: −10 to −5 °F).

When is the last frost in Westminster, MA?

The median last spring frost is May 2 and the median first fall frost is October 13 (NOAA 1991–2020 normals, Ashburnham station).

When can I plant a garden in Westminster, MA?

Cool-season crops like peas and spinach go in around Mar 21 – Apr 11; tomatoes, peppers, beans and squash after about May 9, once frost risk has passed.

What kind of onions grow in Westminster, MA?

Long-day onions: the longest day is 15 h 18 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

How much rain and snow does Westminster, MA get?

About 49.1 inches of precipitation a year (NOAA 1991–2020 normals).