Brockton, Massachusetts: planting zone & frost dates
Brockton is in USDA plant hardiness zone 6b, where the average coldest winter night reaches -5 to 0°F (-20.6 to -17.8°C). The typical last spring frost is around Apr 28 and the first fall frost around Oct 13.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | May 5 | Oct 5 |
| Typical planning date (30% risk) | Apr 28 | Oct 13 |
| Median (50%) | Apr 22 | Oct 19 |
How to read this: after the spring "10% risk" date, a 32°F frost happens in only about 1 year in 10. In fall, the "10% risk" date is the early end — a frost before it happens about 1 year in 10.
Frost data comes from NOAA station BROCKTON, MA (USC00190860), 2.5 mi (4.1 km) from the city center and 39 ft lower than the city center (-12 m). Record used for the 1991–2020 normals: 24 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Brockton
All 2 ZIP codes covering Brockton are in zone 6b.
Vegetable planting calendar for Brockton
Dates are counted from the 30%-risk frost dates above (last frost Apr 28, first frost Oct 13). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Mar 3 – Mar 17 | May 5 – May 19 | — | — |
| Pepper | Feb 17 – Mar 3 | May 12 – May 26 | — | — |
| Lettuce | Mar 17 – Mar 31 | Apr 14 – May 5 | Mar 31 – May 12 | Aug 4 – Sep 1 |
| Green Beans | — | — | May 5 – Jun 9 | Jul 21 – Aug 4 |
| Sweet Corn | — | — | May 5 – Jun 2 | — |
| Zucchini & Summer Squash | Mar 31 – Apr 7 | May 5 – May 19 | May 5 – May 26 | Jul 21 – Aug 4 |
| Cucumber | Mar 31 – Apr 7 | May 12 – May 19 | May 5 – May 26 | Jul 21 – Aug 4 |
| Carrot | — | — | Apr 7 – May 12 | Jul 21 – Aug 4 |
| Onion | Feb 3 – Feb 17 | Mar 31 – Apr 14 | — | — |
| Potato | — | Mar 31 – Apr 21 | — | — |
| Basil | Mar 17 – Mar 31 | May 12 – May 26 | May 12 – Jun 2 | — |
| Spinach | — | — | Mar 17 – Apr 14 | Aug 18 – Sep 15 |
| Kale | Mar 3 – Mar 17 | Mar 31 – Apr 21 | Mar 31 – Apr 21 | Aug 4 – Sep 1 |
| Broccoli | Mar 3 – Mar 17 | Apr 14 – May 5 | — | Jul 21 – Aug 4 |
| Peas | — | — | Mar 17 – Apr 7 | Aug 4 – Aug 18 |
| Eggplant | Feb 17 – Mar 3 | May 12 – May 26 | — | — |
| Cabbage | Mar 3 – Mar 17 | Mar 31 – Apr 14 | — | Jul 21 – Aug 4 |
| Radish | — | — | Mar 24 – May 12 | Sep 1 – Sep 29 |
| Strawberry | — | Mar 31 – Apr 21 | — | — |
| Beets | — | — | Apr 7 – May 19 | Aug 4 – Aug 18 |
Nearby cities in Massachusetts
- Quincy — zone 6b, last frost Apr 30, first frost Oct 15
- Boston — zone 6b, last frost Apr 8, first frost Nov 3
- Cambridge — zone 6b, last frost Apr 8, first frost Nov 3
- Newton — zone 6b, last frost Apr 24, first frost Oct 16
- Somerville — zone 7a, last frost Apr 8, first frost Nov 3
- Fall River — zone 7a, last frost May 5, first frost Oct 9
More: all Massachusetts cities · other zone 6b cities: Columbus, OH, Indianapolis, IN, Boston, MA, Detroit, MI, Kansas City, MO, Cincinnati, OH, Pittsburgh, PA, Buffalo, NY
Brockton gardening questions
When is the last frost in Brockton, MA?
Plan around Apr 28. At NOAA's Brockton, MA station, 2.5 mi from the city center, there is a 30% chance of a 32°F frost after that date. Half of springs have their last frost by Apr 22, and after May 5 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Apr 6. The last frost is fairly predictable here: only 27 days separate the 90% and 10% dates (median for cities on this site: 36 days).
When should I plant tomatoes in Brockton, MA?
Start seeds indoors Mar 3 – Mar 17 and set transplants outside May 5 – May 19, once nights stay above 50°F and the soil is near 60°F. That leaves 168 days between the 30% frost dates, enough for most varieties including 80–85-day slicers. More: tomato planting dates by zone.
How long is the growing season in Brockton?
About 178 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 158 days, and in 1 year in 10 it runs 198 days or more. In fall there is a 10% chance of frost by Oct 5 and a 30% chance by Oct 13. That ranks 6th longest of 13 Massachusetts cities on this site.
When should I plant a fall garden in Brockton?
Count back from the first fall frost (Oct 13): transplant broccoli Jul 21 – Aug 4; sow kale Aug 4 – Sep 1; sow lettuce Aug 4 – Sep 1; sow radishes Sep 1 – Sep 29. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Oct 31. How the math works: succession and fall planting.
Did Brockton's hardiness zone change on the 2023 map?
No. Going by the zone that covers most of the city's land, Brockton is zone 6b on both the 2012 and the 2023 USDA maps (PRISM/OSU ZIP listings). About 42% of U.S. ZIP codes kept their half-zone in 2023. Why the 2023 map is warmer.
How does Brockton compare with Quincy, MA?
Both are in zone 6b. The typical last spring frost in Brockton (Apr 28) comes about the same time as in Quincy, MA (Apr 30), 12 miles away, and the first fall frost is Oct 13 versus Oct 15. The two cities use different NOAA stations.