Boston Weather Averages
Over the course of a year, the weather in Boston, Massachusetts ranges from temperatures in the 90s Fahrenheit (30s Celsius) and thunderstorms to well below freezing and snowstorms. For much of the year though, Boston's climate is relatively mild, thanks to its seaside location.
This page gives detailed information on the annual weather averages for Boston. You can jump directly to data and descriptions for:
The numbers here are historical averages based on climate data gathered at Boston's Logan International Airport, located on the waterfront next to Boston Harbor.
|59 °F||annual average high||15 °C|
|44 °F||annual average low||7 °C|
Boston's coldest days of the year usually occur in mid January when the daily maximum temperature averages 35 degrees Fahrenheit (2 degrees Celsius) and the minimum averages 22 °F (-6 °C).
The year's hottest days are normally in mid July. The average temperature peaks then with daily highs of 82 °F (28 °C) and nighttime lows of 66 °F (19 °C).
|116 days||70 °F maximum or above (21 °C)|
|92 days||32 °F minimum or below (0 °C)|
Boston averages 10 days a year when the thermometer reaches into the 90s °F (over 32 °C). The temperature normally doesn't climb above 100 °F (38 °C), even on the hottest days. Typically on 25 days annually the mercury remains below freezing for the entire day.
The thermometer dips to 10 °F (-12 °C) or below on 7 nights a year. Boston averages less than 1 day a year when the weather gets as cold as 0 °F (-18 °C).
|43.8 inches||total yearly precipitation||1112 millimetres|
|126 days||of rain or snowfall|
March is usually the wettest month of the year in Boston, while February is the driest.
|43.8 inches||total snowfall a year||111.3 centimetres|
|22 days||with new snow|
Most years, it snows in Boston from December to March. On 11 days annually at least an inch (2.5 cm) of snow falls on the city.
|58 %||sunshine annually|
|98 days||with clear skies|
The sun's rays reach the ground in Boston during 58 percent of daylight hours on average year round, for a total of 2590 hours annually. Typically on 98 days a year the sky is mainly clear, with at most 30 percent cloud cover.
Sunlight in Boston lasts for 12 hours and 12 minutes a day on average. The shortest days of the year in mid December have 9 hours and 5 minutes of daylight. The year's longest days in mid June last 15:17 from sunrise to sunset.
|67 %||average humidity|
The annual average for relative humidity in Boston ranges throughout the day from 75 percent at 4:00 am to 58 percent at 1:00 pm.
|Local Time||1 am||4 am||7 am||10 am||1 pm||4 pm||7 pm||10 pm|
|12.3 mph||wind speed average||19.8 kph|
January, February and March are usually the windiest months for Boston, while the wind is calmest during August.
|10 days||precipitation of 1 inch (25 mm) or more|
|3 days||snowfall of 5 inches (13 cm) or more|
|18 days||with thunderstorms a year|
|5.5 %||chance a named storm makes landfall|
Snowstorms that dump 10 inches or more of snow a day are rare in Boston, passing through just once in two years on average.
Thunderstorms usually appear over Boston from March to November, although they can show up in any month.
In any year, there's a 3.2 percent probability that a hurricane will reach land in Suffolk county, which includes Boston. For major hurricanes of category 3 to 5, the likelihood drops to 1.5 percent. Named storms usually arrive during the months of June to October, while hurricanes are generally restricted to August and September.
The chance that a wind gust reaches 40 miles per hour (64 kilometres an hour) or greater is 12.4 percent a year. Intense hurricane force winds that top 115 mph (185 kph) have a 1.2 percent probability of blasting the county.
These weather data are long-term historical averages provided by the National Climatic Data Center of the United States. The temperature and precipitation numbers are 1981-2010 normals while the humidity and thunderstorm statistics are 1961-1990 normals. The named storm and wind gust probability information comes from United States Landfalling Hurricane Probability Project of Colorado State University and Bridgewater State University.