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

Planting zone for 01541 — Princeton, MA

ZIP code 01541 (Princeton, Worcester County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is May 12 and the first fall frost October 1.

Where ZIP 01541 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 frostMay 12
First frostOct 1
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 Princeton, 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 Princeton, MA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 12median — 50% chance of a later frost
Safe for tender plantsMay 28only 10% chance of frost after
First fall frostOctober 1median — 10% chance by Sep 18
Growing season141 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 29 and returns around October 10.

From the NOAA station Barre Falls Dam, MA — 8 miles away, elevation 827 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 01541

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 31 – Apr 14
SpinachSow outdoors · Mar 31 – Apr 21
Broccoli, cabbageStart indoors · Mar 3 – Mar 17
Broccoli, cabbageTransplant · Apr 21 – May 5
Onion setsPlant outdoors · Apr 14 – Apr 28
PotatoesPlant outdoors · Apr 21 – May 5
LettuceSow outdoors · Apr 14 – Apr 28
Carrots, beetsSow outdoors · Apr 21 – May 5
TomatoesStart indoors · Mar 17 – Mar 31
TomatoesTransplant · May 19 – Jun 2
Peppers, eggplantStart indoors · Mar 3 – Mar 17
Peppers, eggplantTransplant · May 26 – Jun 9
BeansSow outdoors · May 19 – Jun 2
Sweet cornSow outdoors · May 19 – Jun 2
Cucumbers, squashSow outdoors · May 19 – Jun 2
Fall lettuce, spinachSow outdoors · Aug 6 – Aug 20
GarlicPlant cloves · Sep 17 – Oct 22
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 12) and first fall frost (Oct 1) 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 01541 came on Apr 12 — about the same time as the 1991–2020 average (Apr 14).

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 Princeton, MA.

Soil in Princeton, MA

The soil mapped at the center of ZIP 01541 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 01541; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Princeton, MA

Summer high83 °Faverage high, July
Winter low13 °Faverage low, January
Hot days9days a year at 90 °F or more
Freezing nights176nights a year at 32 °F or less
Growing degree days2,380base 50 °F — the season’s usable heat
Longest day15 h 18 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)
Precipitation48.3 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 35 °F, low 13 °F 35°13° JanFebruary: average high 38 °F, low 14 °F 38°14° FebMarch: average high 46 °F, low 22 °F 46°22° MarApril: average high 59 °F, low 32 °F 59°32° AprMay: average high 70 °F, low 43 °F 70°43° MayJune: average high 78 °F, low 52 °F 78°52° JunJuly: average high 83 °F, low 58 °F 83°58° JulAugust: average high 81 °F, low 55 °F 81°55° AugSeptember: average high 75 °F, low 48 °F 75°48° SepOctober: average high 62 °F, low 36 °F 62°36° OctNovember: average high 50 °F, low 27 °F 50°27° NovDecember: average high 40 °F, low 19 °F 40°19° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 3.07 in precipitation 3.1 JanFebruary: 3.12 in precipitation 3.1 FebMarch: 4.31 in precipitation 4.3 MarApril: 4.10 in precipitation 4.1 AprMay: 3.66 in precipitation 3.7 MayJune: 4.29 in precipitation 4.3 JunJuly: 3.85 in precipitation 3.9 JulAugust: 4.17 in precipitation 4.2 AugSeptember: 4.29 in precipitation 4.3 SepOctober: 5.06 in precipitation 5.1 OctNovember: 3.96 in precipitation 4.0 NovDecember: 4.37 in precipitation 4.4 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Barre Falls Dam, MA (8 mi away); precipitation: Sterling 4.3 Nw, MA (4 mi away). 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.

015646a
Sterling, MA · 5 mi
015226a
Jefferson, MA · 5 mi
015466a
Shrewsbury, MA · 6 mi
016536b
Worcester, MA · 6 mi
016556a
Worcester, MA · 6 mi
015436a
Rutland, MA · 7 mi
014416a
Westminster, MA · 7 mi
014525b
Hubbardston, MA · 7 mi

Massachusetts planting zones →

Questions about 01541

What planting zone is ZIP code 01541?

ZIP code 01541 (Princeton, 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 Princeton, MA?

The median last spring frost (32 °F) near 01541 is May 12; after May 28 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Barre Falls Dam station.

When is the first frost in Princeton, MA?

The median first fall frost near 01541 is October 1, giving a median frost-free growing season of 141 days.

When should I plant tomatoes in 01541?

Start tomato seeds indoors around Mar 17 – Mar 31 and set transplants outside around May 19 – Jun 2, one to three weeks after the median last frost.

How much rain and snow does 01541 get?

About 48.3 inches of precipitation a year (NOAA 1991–2020 normals, Sterling 4.3 Nw station).

How hot do summers get in Princeton, MA?

The average high peaks at 83 °F in July, with about 9 days a year at 90 °F or more.

What kind of soil does 01541 have?

The USDA soil survey maps Berkshire at the center of ZIP 01541: slightly decomposed plant material, well drained, pH about 3.5 (strongly acidic).

Did spring come early in Princeton, MA in 2026?

Spring leaf-out near 01541 came on Apr 12 in 2026, about the same as the 1991–2020 average (Apr 14), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Princeton, MA?

Long-day onions: the longest day near 01541 is 15 h 18 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).