Weather in Boston, Massachusetts
Roses open along the stoops. Day 59 of spring. Read this microseason across nine climate regions →
- TodayMay 16Overcast—79°46°
- SundayMay 17Overcast19%88°62°
- MondayMay 18Overcast—70°55°
- TuesdayMay 19Rain20%96°60°
- WednesdayMay 20Showers75%94°62°
- ThursdayMay 21Overcast22%68°54°
- FridayMay 22Overcast—70°51°
- PM 2.5
- 10.3 μg/m³
- PM 10
- 13.3 μg/m³
- NO₂
- 9.2 μg/m³
- Ozone
- 94.0 μg/m³
- UV Index
- 0.0 Low
When the dew is on the grass, rain will never come to pass.
- Moonrise
- 9:22 AM
- Moonset
- 12:28 AM
- In sign
- ♊︎ Gemini
Roses open along the stoops
Boston at a glance
- Today vs. normal: 5°F below the seasonal normal for this latitude
- Last frost: April 30 (climatological average for this latitude)
- Microseason: 28 of 72, May 16–20
- Planting window: Direct sow okra, melons, and southern peas. Thin carrot rows.
Right now in the garden
Cool-season window is open
As of May 17, the cool-season window is open or about to open. Direct-sow peas, lettuce, spinach, radishes, and brassicas now. Hold off on warm-season crops until 1–2 weeks after the last spring frost (around May).
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | — | — |
| February | — | — |
| March | — | — |
| April | — | — |
| May | lettuce, peas, spinach, radishes | lettuce, peas, radishes |
| June | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| July | tomatoes, peppers, beans, squash | tomatoes, beans, summer squash |
| August | tomatoes, peppers, beans, squash, fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| September | fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| October | — | winter squash, tomatoes (last) |
| November | — | — |
| December | — | — |
A year in weather
July ranks as Boston's warmest month with mean temperatures around 74°F, while January stands as the coldest at roughly 28°F. December brings peak rainfall at 5.1 inches, contrasting with July's lighter 3.5 inches.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 28° | 3.9″ | 13 |
| February | 30° | 3.6″ | 12 |
| March | 38° | 4.5″ | 15 |
| April | 49° | 4.3″ | 14 |
| May | 59° | 3.6″ | 12 |
| June | 68° | 4.2″ | 14 |
| July | 74° | 3.5″ | 12 |
| August | 73° | 3.7″ | 12 |
| September | 65° | 4.0″ | 13 |
| October | 53° | 5.0″ | 17 |
| November | 43° | 4.0″ | 13 |
| December | 34° | 5.1″ | 17 |
Regional context
Boston falls within a warm-summer humid continental climate region. Cities in this zone experience comparable temperature ranges, seasonal patterns, and growing conditions throughout the surrounding area.
Similar climates: Worcester, MA, Springfield, MA, New Bedford, MA, Cambridge, MA, Lowell, MA.
Naturalist notes
Late May brings the emergence of mayapple umbrellas unfurling across woodland floors throughout the Boston area.
Spring peepers begin their evening chorus in March as temperatures climb above freezing consistently.
Frequently asked
- When does it freeze in Boston?
- Boston's final spring frost usually occurs around mid-May, while the first fall frost typically arrives around mid-October.
- What is the rainy season in Boston?
- December records the highest rainfall with approximately 5.1 inches on average; Boston receives roughly 49 inches annually.
- What is the warmest month in Boston?
- July typically registers as the warmest month, averaging about 74°F.
- What is the coldest month in Boston?
- January typically registers as the coldest month, averaging about 28°F.
- When can I start a vegetable garden in Boston?
- Cool-season crops like peas and lettuce can be planted around the last spring frost in mid-May; warm-season crops such as tomatoes and peppers should wait until 1–2 weeks after.
- How many rainy days does Boston get?
- Boston records about 164 rainy days per year on average.
- What hardiness zone is Boston?
- Boston's USDA hardiness zone depends on its lowest average winter temperature; consult the USDA's online lookup using the city ZIP for the current zone designation.
Climate
Boston, Massachusetts experiences a warm-summer humid continental climate zone. Winter temperatures in January typically hover near 28°F, while July averages reach 74°F — creating a 46°F seasonal swing.
Throughout the year, Boston collects about 49 inches of precipitation distributed across roughly 164 rainy days.
Several factors determine the city's seasonal patterns: its latitude at 42.3°N, proximity to large water bodies, and elevation. These elements influence local plant growth, frost timing, and daily weather conditions.