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

Planting zone for 01226 — Dalton, MA

ZIP code 01226 (Dalton, Berkshire County) is in USDA zone 5b: the coldest winter night averages −15 to −10 °F. The median last spring frost is May 5 and the first fall frost October 5.

Where ZIP 01226 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.

Zone5b−15 to −10 °F
Coldest night−26.1 to −23.3 °C
Last frostMay 5
First frostOct 5
2012 zone5a

Was 5a 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 5b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Dalton, 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 Dalton, MA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 5median — 50% chance of a later frost
Safe for tender plantsMay 21only 10% chance of frost after
First fall frostOctober 5median — 10% chance by Sep 23
Growing season152 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 23 and returns around October 18.

From the NOAA station Pittsfield Municipal Airport, MA — 8 miles away, elevation 1,194 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 01226

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 24 – Apr 7
SpinachSow outdoors · Mar 24 – Apr 14
Broccoli, cabbageStart indoors · Feb 24 – Mar 10
Broccoli, cabbageTransplant · Apr 14 – Apr 28
Onion setsPlant outdoors · Apr 7 – Apr 21
PotatoesPlant outdoors · Apr 14 – Apr 28
LettuceSow outdoors · Apr 7 – Apr 21
Carrots, beetsSow outdoors · Apr 14 – Apr 28
TomatoesStart indoors · Mar 10 – Mar 24
TomatoesTransplant · May 12 – May 26
Peppers, eggplantStart indoors · Feb 24 – Mar 10
Peppers, eggplantTransplant · May 19 – Jun 2
BeansSow outdoors · May 12 – May 26
Sweet cornSow outdoors · May 12 – May 26
Cucumbers, squashSow outdoors · May 12 – May 26
Fall lettuce, spinachSow outdoors · Aug 10 – Aug 24
GarlicPlant cloves · Sep 21 – Oct 26
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 5) and first fall frost (Oct 5) 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 01226 came on Apr 12 — 8 days earlier than the 1991–2020 average (Apr 20).

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 5b in Massachusetts

527 plants native to the lower 48 states, recorded in Massachusetts, and rated by the USDA to survive −15 °F or colder — the bottom of zone 5b. 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 104

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 181

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 154

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 7

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 honeysuckle16 ft · blooms late summer · low shade tolerance · to −33 °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 Dalton, MA.

Soil in Dalton, MA

The center of ZIP 01226 is mapped as Udorthents, smoothed: built-over ground without natural soil data. Garden soil here is usually imported or disturbed — test before you plant.

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 01226; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Dalton, MA

Summer high79 °Faverage high, July
Winter low14 °Faverage low, January
Hot days3days a year at 90 °F or more
Freezing nights153nights a year at 32 °F or less
Growing degree days2,169base 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)
Precipitation44.2 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 30 °F, low 14 °F 30°14° JanFebruary: average high 33 °F, low 15 °F 33°15° FebMarch: average high 42 °F, low 23 °F 42°23° MarApril: average high 55 °F, low 34 °F 55°34° AprMay: average high 67 °F, low 44 °F 67°44° MayJune: average high 75 °F, low 53 °F 75°53° JunJuly: average high 79 °F, low 58 °F 79°58° JulAugust: average high 78 °F, low 57 °F 78°57° AugSeptember: average high 70 °F, low 49 °F 70°49° SepOctober: average high 58 °F, low 39 °F 58°39° OctNovember: average high 47 °F, low 29 °F 47°29° NovDecember: average high 36 °F, low 21 °F 36°21° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 2.67 in precipitation 2.7 JanFebruary: 2.52 in precipitation 2.5 FebMarch: 3.08 in precipitation 3.1 MarApril: 3.38 in precipitation 3.4 AprMay: 3.79 in precipitation 3.8 MayJune: 4.58 in precipitation 4.6 JunJuly: 4.18 in precipitation 4.2 JulAugust: 3.82 in precipitation 3.8 AugSeptember: 4.50 in precipitation 4.5 SepOctober: 4.56 in precipitation 4.6 OctNovember: 3.52 in precipitation 3.5 NovDecember: 3.63 in precipitation 3.6 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Pittsfield Municipal Airport, MA (8 mi away); precipitation: Pittsfield Municipal Airport, MA (8 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5b.

012275b
Dalton, MA · <1 mi
012245b
Berkshire, MA · 3 mi
012255b
Cheshire, MA · 6 mi
012355b
Hinsdale, MA · 6 mi
012705b
Windsor, MA · 6 mi
012015b
Pittsfield, MA · 7 mi
012025b
Pittsfield, MA · 7 mi
012035b
Pittsfield, MA · 7 mi

All 2 ZIP codes in Dalton → · Massachusetts planting zones →

Questions about 01226

What planting zone is ZIP code 01226?

ZIP code 01226 (Dalton, MA) is in USDA hardiness zone 5b on the 2023 map: the coldest night of an average winter reaches −15 to −10 °F (−26.1 to −23.3 °C).

When is the last frost in Dalton, MA?

The median last spring frost (32 °F) near 01226 is May 5; after May 21 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Pittsfield Municipal Airport station.

When is the first frost in Dalton, MA?

The median first fall frost near 01226 is October 5, giving a median frost-free growing season of 152 days.

When should I plant tomatoes in 01226?

Start tomato seeds indoors around Mar 10 – Mar 24 and set transplants outside around May 12 – May 26, one to three weeks after the median last frost.

How much rain and snow does 01226 get?

About 44.2 inches of precipitation a year (NOAA 1991–2020 normals, Pittsfield Municipal Airport station).

How hot do summers get in Dalton, MA?

The average high peaks at 79 °F in July, with about 3 days a year at 90 °F or more.

Did spring come early in Dalton, MA in 2026?

Spring leaf-out near 01226 came on Apr 12 in 2026, 8 days earlier than the 1991–2020 average (Apr 20), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Dalton, MA?

Long-day onions: the longest day near 01226 is 15 h 18 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 01226 change?

Yes. The 2012 USDA map put 01226 in zone 5a; the 2023 map puts it in zone 5b. The newer map uses 1991–2020 data and more weather stations.