September in Boston, Massachusetts, typically marks a transition from summer’s heat to autumn’s crispness. Average high temperatures gradually decrease from the low 70s Fahrenheit (low 20s Celsius) at the beginning of the month to the mid-60s Fahrenheit (high teens Celsius) by the end. Overnight lows follow a similar trend, moving from the upper 50s Fahrenheit (mid-teens Celsius) to the lower 50s Fahrenheit (low teens Celsius). This period is characterized by diminishing humidity and increasingly frequent sunny days, punctuated by occasional periods of rain.
Understanding the typical climate conditions during this month is valuable for planning various activities, including outdoor events, travel, and seasonal wardrobe choices. Historically, September has offered a pleasant respite from summer’s heat while still providing ample opportunity to enjoy outdoor activities before the arrival of colder weather. This period often coincides with the vibrant foliage displays that begin in the northern parts of New England and gradually progress southward.