Quincy, Massachusetts: planting zone & frost dates
Quincy 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 30 and the first fall frost around Oct 15.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | May 8 | Oct 6 |
| Typical planning date (30% risk) | Apr 30 | Oct 15 |
| Median (50%) | Apr 25 | Oct 22 |
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 HINGHAM, MA (USC00193624), 5.5 mi (8.8 km) from the city center and 33 ft higher than the city center (+10 m). Record used for the 1991–2020 normals: 30 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Quincy
Quincy spans more than one half-zone. Share of the city's land area by zone (via its 3 ZIP codes): 6b (73%), 7a (27%). The headline zone is the one covering the most land. Look up your ZIP for your exact zone.
Vegetable planting calendar for Quincy
Dates are counted from the 30%-risk frost dates above (last frost Apr 30, first frost Oct 15). 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 5 – Mar 19 | May 7 – May 21 | — | — |
| Pepper | Feb 19 – Mar 5 | May 14 – May 28 | — | — |
| Lettuce | Mar 19 – Apr 2 | Apr 16 – May 7 | Apr 2 – May 14 | Aug 6 – Sep 3 |
| Green Beans | — | — | May 7 – Jun 11 | Jul 23 – Aug 6 |
| Sweet Corn | — | — | May 7 – Jun 4 | — |
| Zucchini & Summer Squash | Apr 2 – Apr 9 | May 7 – May 21 | May 7 – May 28 | Jul 23 – Aug 6 |
| Cucumber | Apr 2 – Apr 9 | May 14 – May 21 | May 7 – May 28 | Jul 23 – Aug 6 |
| Carrot | — | — | Apr 9 – May 14 | Jul 23 – Aug 6 |
| Onion | Feb 5 – Feb 19 | Apr 2 – Apr 16 | — | — |
| Potato | — | Apr 2 – Apr 23 | — | — |
| Basil | Mar 19 – Apr 2 | May 14 – May 28 | May 14 – Jun 4 | — |
| Spinach | — | — | Mar 19 – Apr 16 | Aug 20 – Sep 17 |
| Kale | Mar 5 – Mar 19 | Apr 2 – Apr 23 | Apr 2 – Apr 23 | Aug 6 – Sep 3 |
| Broccoli | Mar 5 – Mar 19 | Apr 16 – May 7 | — | Jul 23 – Aug 6 |
| Peas | — | — | Mar 19 – Apr 9 | Aug 6 – Aug 20 |
| Eggplant | Feb 19 – Mar 5 | May 14 – May 28 | — | — |
| Cabbage | Mar 5 – Mar 19 | Apr 2 – Apr 16 | — | Jul 23 – Aug 6 |
| Radish | — | — | Mar 26 – May 14 | Sep 3 – Oct 1 |
| Strawberry | — | Apr 2 – Apr 23 | — | — |
| Beets | — | — | Apr 9 – May 21 | Aug 6 – Aug 20 |
Nearby cities in Massachusetts
- Boston — zone 6b, last frost Apr 8, first frost Nov 3
- Somerville — zone 7a, last frost Apr 8, first frost Nov 3
- Cambridge — zone 6b, last frost Apr 8, first frost Nov 3
- Brockton — zone 6b, last frost Apr 28, first frost Oct 13
- Newton — zone 6b, last frost Apr 24, first frost Oct 16
- Lynn — zone 7a, last frost May 1, first frost Oct 14
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
Quincy gardening questions
When is the last frost in Quincy, MA?
Plan around Apr 30. At NOAA's Hingham, MA station, 5.5 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 25, and after May 8 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Apr 10. The last frost is fairly predictable here: only 25 days separate the 90% and 10% dates (median for cities on this site: 36 days).
When should I plant tomatoes in Quincy, MA?
Start seeds indoors Mar 5 – Mar 19 and set transplants outside May 7 – May 21, 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 Quincy?
About 177 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 197 days or more. In fall there is a 10% chance of frost by Oct 6 and a 30% chance by Oct 15. That ranks 7th longest of 13 Massachusetts cities on this site.
When should I plant a fall garden in Quincy?
Count back from the first fall frost (Oct 15): transplant broccoli Jul 23 – Aug 6; sow kale Aug 6 – Sep 3; sow lettuce Aug 6 – Sep 3; sow radishes Sep 3 – Oct 1. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Nov 2. How the math works: succession and fall planting.
Did Quincy's hardiness zone change on the 2023 map?
No. Going by the zone that covers most of the city's land, Quincy 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.
Is all of Quincy in zone 6b?
No. Zone 6b covers about 73% of the city's land; the rest is in 7a (27%), measured across the city's 3 ZIP codes. Check your own ZIP code in the table above or with the ZIP lookup.