Last frost date in Somerville, MA
In Somerville, the last spring frost comes around April 4 in an average year. Wait until April 17 if you want 90% odds of no more frost. The first fall frost usually arrives about November 9, which leaves 218 frost-free days. An early freeze before October 29 happens one year in ten.
- Safe after (10% risk)
- Apr 17
- Average first frost
- Nov 9
- Frost-free season
- 218 days
- Hard freeze (28°F) ends
- Mar 28
Frost possible in low spots Fri night, low 33°F
Earlier than usual: the average first frost here is November 9.
National Weather Service forecast, updated Oct 22, 12:57 UTC
- ThuOct 2239°
- FriOct 2333°possible frost
- SatOct 2434°possible frost
- SunOct 2539°
- MonOct 2645°
- TueOct 2741°
- WedOct 2841°
Planting calendar for Somerville
Windows count forward or back from the average frost dates above. Click a crop for dates across Massachusetts.
TomatoesApr 11–Apr 25
PumpkinsApr 18–May 2
SunflowersApr 4–Apr 25
CucumbersApr 18–Apr 25
CornApr 11–Apr 25
Sweet potatoesApr 25–May 9
WatermelonApr 18–May 2
Green beansApr 11–May 2
ZucchiniApr 11–Apr 25
OkraApr 25–May 9
PeppersApr 18–May 2
BasilApr 11–Apr 25
Butternut squashApr 11–Apr 25
CantaloupeApr 18–May 2
EggplantApr 18–May 2
PotatoesMar 7–Mar 21
OnionsFeb 21–Mar 14
CarrotsMar 14–Apr 18
LettuceMar 21–Apr 11
BroccoliMar 7–Mar 21
BeetsMar 7–Apr 18
PeasFeb 21–Mar 7
CabbageMar 7–Mar 21
RadishesFeb 28–Apr 11
Brussels sproutsMar 21–Apr 4
SpinachFeb 21–Mar 14
CilantroMar 21–Apr 11
KaleMar 7–Mar 21
Collard greensMar 7–Mar 21
TurnipsMar 7–Mar 21
DillApr 4–Apr 18
CeleryApr 11–Apr 18
CauliflowerMar 21–Apr 4
LeeksMar 21–Apr 4
Swiss chardMar 21–Apr 18
ParsleyMar 21–Apr 11
Tulip bulbsOct 26–Nov 30
GarlicOct 19–Nov 23
Daffodil bulbsOct 12–Nov 23
StrawberriesMar 7–Mar 21
AsparagusMar 7–Mar 21Frost probabilities
| Threshold | Spring, 90% chance later | Spring, 50% | Spring, 10% | Fall, 10% chance earlier | Fall, 50% | Fall, 90% |
|---|---|---|---|---|---|---|
| Light frost, 32°F | Mar 25 | Apr 4 | Apr 17 | Oct 29 | Nov 9 | Nov 22 |
| Hard freeze, 28°F | Mar 15 | Mar 28 | Apr 6 | Nov 8 | Nov 21 | Dec 5 |
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 Boston Logan International Airport (USW00014739) sits 5.1 miles from the center of Somerville at 12 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 Somerville, MA?
The average last frost date in Somerville is April 4, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after April 17.
When is the first frost in Somerville?
The first frost in fall usually comes around November 9. One year in ten it arrives before October 29.
How long is the growing season in Somerville?
About 218 days between the average last and first frost.
When should I plant tomatoes in Somerville?
Plant tomato seedlings outside from April 11 to April 25. Start seeds indoors six to eight weeks earlier.