What is the Weather in Boston in September?

Updated: Januar 24, 2024

This post is an overview of the September weather in Boston, with tips on how to dress and things to do to help make the most of your trip. 


September usually starts out warm in Boston but can end a bit on the cool side.

Daytime high temperatures tend to average in mid to upper 70s F (about 25 C) early in September but drop off into the mid-upper 60s F (19C to 20C) by the end of the month.

A few of the warmer afternoons early in the month reach into to mid-80s F (about 30C) with one day reaching 90 F (about 32C) or more about once every other year.

Average Temperatures September Boston

The record high temperature recorded in Boston during September was 100 F (37.8C)!

Late night and early morning low temperatures will be trending colder this month. Early in September, the lows tend to be in the lower 60s F (16C to 17C) but fall into the low to mid-50s F (11C to 12C) by the month’s end.

A few of the colder mornings towards the end of the month will dip down into the mid-40s F (6C to 7C). The record low in Boston during September was 38 F (3.3C).

In short, September is one of the best month of the year to take a free walking tour.


September is a good month to explore Boston as about 20 days this month will be either sunny or at least partly sunny.

Measurable rainfall occurs on 8-9 days but heavy rains of 0.5 inches (12.7 mm) or more only are expected on 2 days.

Boston in September Weather Calendar

You can expect just over 13 hours of daylight early in September but decreasing to just short of 12 hours by the end of the month.


Summer is ending and September starts to become more fall-like so you will need to bring some summer attire as well as clothes for the cooler fall days.

What to Wear in Boston in September

Best to bring a sweater, windbreaker or light jacket for the cooler nights and mornings and don’t forget some good walking shoes.


Be sure to read our full post on what to do in Boston in September, which includes free things to do, night and family-friendly activities and attractions

You may also find our master post on the best things to do in Boston helpful as well.

And if you are planning on visiting many of Boston’s top attractions, then you should consider a tourist discount pass as you could save up to 50% of retail ticket prices to tours, attractions, and restaurants.

Some of the fun activities include: 

Seasonal Outlook

July to September 2024 Boston

There is a 92% chance for normal to above normal temperatures with near normal rainfall.

Fred Pickhardt
Ocean Weather Services

Look into the weather in August and October, as well.

About The Author

Brian Burgess

I was born in Cambridge and have been living in the Boston area all my life. I am a graduate of Boston's Emerson College with a degree in communications with a journalism/history focus. I have been leading tours for Free Tours By Foot Boston since it was started in the city of Boston in 2012, and enjoy sharing my knowledge of Boston's rich history with not only the guests on my tours, but with everyone I meet. <a href="https://freetoursbyfoot.com/contributors/brian-burgess/" Read More...
Updated: Januar 24th, 2024
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