Last frost date in Dedham, MA
Expect the last frost in Dedham around April 25. Frost after May 11 happens in only one year out of ten. The first fall frost usually arrives about October 9, which leaves 167 frost-free days. An early freeze before September 28 happens one year in ten.
- Safe after (10% risk)
- May 11
- Average first frost
- Oct 9
- Frost-free season
- 167 days
- Hard freeze (28°F) ends
- Apr 8
Frost likely Fri night, low 31°F
National Weather Service forecast, updated Oct 22, 12:24 UTC
- ThuOct 2237°
- FriOct 2331°frost
- SatOct 2432°frost
- SunOct 2537°
- MonOct 2643°
- TueOct 2739°
- WedOct 2841°
Planting calendar for Dedham
Windows count forward or back from the average frost dates above. Click a crop for dates across Massachusetts.
TomatoesMay 2–May 16
PumpkinsMay 9–May 23
SunflowersApr 25–May 16
CucumbersMay 9–May 16
CornMay 2–May 16
Sweet potatoesMay 16–May 30
WatermelonMay 9–May 23
Green beansMay 2–May 23
ZucchiniMay 2–May 16
OkraMay 16–May 30
PeppersMay 9–May 23
BasilMay 2–May 16
Butternut squashMay 2–May 16
CantaloupeMay 9–May 23
EggplantMay 9–May 23
PotatoesMar 28–Apr 11
OnionsMar 14–Apr 4
CarrotsApr 4–May 9
LettuceApr 11–May 2
BroccoliMar 28–Apr 11
BeetsMar 28–May 9
PeasMar 14–Mar 28
CabbageMar 28–Apr 11
RadishesMar 21–May 2
Brussels sproutsApr 11–Apr 25
SpinachMar 14–Apr 4
CilantroApr 11–May 2
KaleMar 28–Apr 11
Collard greensMar 28–Apr 11
TurnipsMar 28–Apr 11
DillApr 25–May 9
CeleryMay 2–May 9
CauliflowerApr 11–Apr 25
LeeksApr 11–Apr 25
Swiss chardApr 11–May 9
ParsleyApr 11–May 2
Tulip bulbsSep 25–Oct 30
GarlicSep 18–Oct 23
Daffodil bulbsSep 11–Oct 23
StrawberriesMar 28–Apr 11
AsparagusMar 28–Apr 11Frost probabilities
| Threshold | Spring, 90% chance later | Spring, 50% | Spring, 10% | Fall, 10% chance earlier | Fall, 50% | Fall, 90% |
|---|---|---|---|---|---|---|
| Light frost, 32°F | Apr 9 | Apr 25 | May 11 | Sep 28 | Oct 9 | Oct 30 |
| Hard freeze, 28°F | Mar 26 | Apr 8 | Apr 27 | Oct 6 | Oct 23 | Nov 9 |
Read the spring 10% column as the date after which only one year in ten still gets frost. That is the safer date for tomatoes, peppers and basil.
Where these numbers come from
NOAA station Norwood Mem Airport (USW00054704) sits 3.9 miles from the center of Dedham at 50 feet. Its averages cover 1991 to 2020. Low spots, valleys and open fields can keep getting frost a week or two after the station stops; city centers and lakeshores usually get less of it.
Questions
When is the last frost in Dedham, MA?
The average last frost date in Dedham is April 25, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after May 11.
When is the first frost in Dedham?
The first frost in fall usually comes around October 9. One year in ten it arrives before September 28.
How long is the growing season in Dedham?
About 167 days between the average last and first frost.
When should I plant tomatoes in Dedham?
Plant tomato seedlings outside from May 2 to May 16. Start seeds indoors six to eight weeks earlier.