USDA zone 6b in Massachusetts
USDA plant hardiness zone 6b covers 31 locations across Massachusetts (average annual extreme minimum −5 to 0 °F): Amesbury, MA, Attleboro, MA, Beverly, MA, Boston, MA, Danvers, MA, Framingham, MA, and 25 more. Average last spring frost across this group ranges April 4 (Medford) to May 4 (Salisbury), and growing seasons run 156–218 days (Framingham to Medford) — even within one state, because hardiness sets winter survival, not planting dates. The table below gives every Massachusetts location's own frost dates; the printable planting calendar uses Southbridge, this group's median-season location.
- USDA zone
- 6b−5 to 0 °F
- Last frost range
- Apr 4–May 4avg, 32°F
- First frost range
- Oct 6–Nov 9avg, 32°F
- Growing season range
- 156–218days
Locations in this group
Every location below shares this zone and a nearby weather station, but keeps its own frost dates — find your town for its own numbers, or use the ZIP planner on the home page for an instant personalized answer.
| Location | Also covers | Nearest station | Last frost | First frost | Season (days) |
|---|---|---|---|---|---|
| Amesbury | Newburyport, Boxford, Rowley | Groveland | May 3 | Oct 8 | 158 |
| Attleboro | Mansfield Center, Norton Center | Norton W | Apr 27 | Oct 15 | 168 |
| Beverly | Lynn | Marblehead | Apr 25 | Oct 20 | 176 |
| Boston | Newton, Milton, Waltham, Needham, Dedham, Wellesley, +5 more | Jamaica Plain | Apr 19 | Oct 23 | 185 |
| Danvers | Reading, Lynnfield, Topsfield | Middleton | May 3 | Oct 9 | 157 |
| Framingham | Marlborough, Hudson, Maynard, Cochituate, West Concord, Cordaville | Maynard 2 | May 2 | Oct 6 | 156 |
| Franklin | North Attleborough, Norwood, Medfield, Dover, Cochituate, Millis-Clicquot, +4 more | Walpole 2 | Apr 27 | Oct 14 | 169 |
| Hanscom AFB | — | Bedford | Apr 27 | Oct 13 | 169 |
| Haverhill | — | Haverhill | May 1 | Oct 12 | 163 |
| Hudson | South Lancaster | Fitchburg Muni Ap | Apr 29 | Oct 11 | 164 |
| Kingston | West Wareham, White Island Shores | Plymouth Muni Ap | Apr 30 | Oct 16 | 170 |
| Longmeadow | Windsor Locks, Broad Brook, Hazardville, Simsbury Center, Salmon Brook, Somers, +4 more | Hartford Bradley Intl Ap | Apr 21 | Oct 16 | 177 |
| Lowell | Littleton Common | Lowell | Apr 30 | Oct 10 | 164 |
| Medford | Malden, Somerville | Boston Logan Intl Ap | Apr 4 | Nov 9 | 218 |
| Methuen | Wilmington, Lawrence, Andover | Lawrence | Apr 13 | Oct 28 | 198 |
| Milford | Upton, Hopkinton | West Medway | Apr 30 | Oct 9 | 162 |
| Milton | Norwood, Dedham, Randolph, Holbrook, Sharon | Blue Hill Coop | Apr 18 | Oct 26 | 190 |
| North Attleborough | Woonsocket, Greenville, Bellingham, Whitinsville, Valley Falls, Cumberland Hill, +1 more | Woonsocket | Apr 22 | Oct 19 | 179 |
| North Lakeville | Middleborough Center | Rochester | Apr 23 | Oct 21 | 180 |
| Peabody | Beverly, Danvers, Topsfield, Essex, Ipswich | Beverly Muni Ap | Apr 24 | Oct 17 | 177 |
| Salisbury | Hampton, Kittery Point, Seabrook Beach | Greenland | May 4 | Oct 8 | 157 |
| Southbridge * | Sturbridge, Quinebaug, Monson Center, Witches Woods | E Brimfield Lake | Apr 28 | Oct 15 | 169 |
| Springfield | Agawam, West Springfield, North Granby | Westfield Barnes Muni Ap | May 3 | Oct 8 | 158 |
| Taunton | Bridgewater, Brockton, Abington, Holbrook, Raynham Center, Hanson | Brockton | Apr 22 | Oct 19 | 178 |
| Taunton | North Lakeville | Taunton Muni Ap | May 2 | Oct 8 | 158 |
| Taunton | — | Taunton | Apr 22 | Oct 19 | 179 |
| Webster | Mechanicsville, Lake Bungee, Quasset Lake | W Thompson Lake | May 1 | Oct 9 | 161 |
| West Concord | Hanscom AFB | Bedford Hanscom Fld | Apr 28 | Oct 10 | 165 |
| Weymouth | Quincy, Braintree, Abington, Hanson | Hingham | Apr 25 | Oct 22 | 177 |
| Wilmington | Lexington, Woburn, Burlington, Saugus, Reading, Wakefield, +5 more | Reading | Apr 25 | Oct 17 | 174 |
| Worcester | Oxford, East Douglas, Northborough, Upton, Spencer, Westborough | Worcester Rgnl Ap | Apr 23 | Oct 21 | 181 |
* Southbridge is this group's median-season location — the calendar below is computed from its data.
Data: NOAA NCEI U.S. Climate Normals 1991–2020 (public domain) and USDA Plant Hardiness Zone Map 2023. Planting windows synthesized from U.S. Cooperative Extension guides.
Planting calendar (Southbridge, representative)
Computed from Southbridge's average frost dates — the median-season location in this Massachusettszone 6b group. hatched = start seeds indoors, solid green = plant out, teal = a fall sowing, and the terracotta dot marks the estimated first harvest. Ranges are extension-guide planning guidance, not guarantees — your own location's dates may run a week or two earlier or later (see the table above).
- Start indoors
- Plant out
- Fall sowing
- First harvest
| Crop | Frost tolerance | Start indoors | Plant out | First harvest | Fall planting | Season fit |
|---|---|---|---|---|---|---|
| Tomato | Tender | Mar 3 – Mar 17 | May 5 – May 12 | Jul 4 – Jul 24 | — | matures comfortably |
| Pepper | Very tender | Feb 17 – Mar 3 | May 12 – May 19 | Jul 11 – Aug 10 | — | matures comfortably |
| Cucumber | Tender | Mar 31 – Apr 7 | May 5 – May 12 | Jun 24 – Jul 14 | — | matures comfortably |
| Summer squash / zucchini | Tender | — | May 5 – May 12 | Jun 19 – Jul 4 | — | matures comfortably |
| Bush bean | Tender | — | May 5 – May 12 | Jun 24 – Jul 4 | Aug 16 – Aug 26 | matures comfortably |
| Sweet corn | Tender | — | Apr 28 – May 12 | Jun 27 – Jul 27 | — | matures comfortably |
| Basil | Very tender | Mar 17 – Mar 31 | May 5 – May 12 | Jun 4 – Jun 19 | — | matures comfortably |
| Lettuce | Half-hardy | Mar 17 – Mar 31 | Mar 31 – Apr 14 | May 15 – May 30 | Aug 2 – Aug 17 | matures comfortably |
| Pea | Hardy | — | Mar 17 – Mar 31 | May 11 – May 26 | Jul 23 – Aug 7 | matures comfortably |
| Spinach | Hardy | — | Mar 17 – Mar 31 | Apr 26 – May 6 | Aug 12 – Aug 22 | matures comfortably |
| Carrot | Half-hardy | — | Apr 7 – Apr 14 | Jun 6 – Jun 26 | Jul 13 – Aug 2 | matures comfortably |
| Broccoli | Half-hardy | Mar 3 – Mar 17 | Mar 31 – Apr 14 | May 25 – Jun 14 | Jul 18 – Aug 7 | matures comfortably |
Which crops fit this growing season
Using Southbridge's own 169-day growing season (32°F, NOAA 1991–2020 median) against each crop's real days-to-maturity range: 12 of 12 crops mature here with comfortable margin. A different location in the table above with a longer or shorter season will get a different mix — the ZIP planner on the home page gives your own.
Frost & freeze dates (Southbridge)
From NOAA's 1991–2020 Climate Normals at station USC00192107. The median (p50) is the average date; the 90%-safe column is the date the freeze has passed in about 9 years out of 10 — the conservative date to plant after or harvest before.
| Threshold | Last spring — avg | Last spring — 90%-safe | First fall — avg | First fall — 90%-safe | Season (days) |
|---|---|---|---|---|---|
| 36°F | May 11 | May 26 | Oct 4 | Oct 19 | 147 |
| 32°F (freeze) | Apr 28 | May 17 | Oct 15 | Nov 1 | 169 |
| 28°F | Apr 13 | May 2 | Oct 27 | Nov 11 | 194 |
| 24°F | Apr 2 | Apr 15 | Nov 5 | Nov 23 | 217 |
Growing degree days
Growing degree days (GDD) accumulate warmth above a base temperature over the year — a better predictor of crop development than the calendar alone. This group's median GDD (base 50°F) across all 31 locations is 2,755; Southbridge's own reading is shown below.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 2,517 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 4,579 | cool-season crops (brassicas, greens) |
Hardiness zone 6b in Massachusetts
Zone 6b means an average annual extreme minimum winter temperature of about −5 to 0 °F on the USDA's 2023 map — the number that tells you which perennials, shrubs, and trees reliably survive an average winter here. It does not set your planting dates, which come from the frost calendar above. Massachusetts spans 5 hardiness zones in this dataset — see all Massachusetts locations for the full range, including zones5b, 6a, 7a, 7b.
Explore zone 6b in other states at zone 6b, or see all USDA hardiness zones.
Frequently asked questions
- What does USDA hardiness zone 6b mean in Massachusetts?
- Zone 6b means an average annual extreme minimum winter temperature of −5 to 0 °F — the standard USDA measure of which perennials survive winter. 31 locations in Massachusetts fall in this zone. It does not set planting dates; see the frost calendar below for that.
- Where in Massachusetts's zone 6b is the growing season longest?
- Medford runs the longest season on this page at about 218 days; Framingham is shortest at about 156 days — they share the same hardiness zone, but they sit at different weather stations, so their frost calendars differ.
- When should I plant tomatoes in Massachusetts's zone 6b?
- Using Southbridge's frost dates (this page's median-season location): start seeds indoors about Mar 3 – Mar 17, then transplant outside about May 5 – May 12. Your own location in the table above may differ by a week or two — use the ZIP planner on the home page for your exact station's dates.
- Does every location in Massachusetts's zone 6b have the same frost dates?
- No — they do not all share a weather station, so frost dates vary by a week or more across the 31 locations listed (see the table above for each location's own dates).
Sources & method
Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020, one reading per location's own nearest station (see the table above). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to each location's ZIP. Planting windows are computed by counting from the average last and first frost using per-crop offsets synthesized from U.S. Cooperative Extension guides — the full method and citations are on the methodology page.