Early autumn · Weather & things to do
Boston in September
Boston cools off: highs slip to 75°F (24°C), from 82°F in August, with lows of 56°F (13°C) and about 3.6 in (92 mm) of rain.
At 83/100 for comfort (the top score of the year), it's one of the best months to visit.
- Avg high
- 75°F (24°C)
- Avg low
- 56°F (13°C)
- Rain
- 3.6 in (92 mm)
- Humidity
- 75%
- Cloud cover
- 51%
- Daylight
- ~12 h 16 min
- Comfort score
- 83/100 · Great
What September feels like
Days are warm, averaging 75°F (24°C), easy weather for being outside from morning to evening.
Lows average 56°F (13°C).
Some rain is likely, about 3.6 in (92 mm) in the month, so pack for a shower or two.
Plan around September
September is one of Boston's best months on the climate data.
- Last warm month for a while: October highs fall to 62°F.
- Comfort holds steady from August (81 → 83/100).
- September sits inside the May – Oct window our Boston to Portland route recommends.
What to pack for September
- Light, breathable clothes75°F afternoons
- Packable rain jacket or umbrellaabout 3.6 in of rain
- Comfortable walking shoesmost places below are best reached on foot or with short walks
What to do in Boston in September
September is good outdoor weather here, so these picks lean toward the open air.
Fenway Park
Baseball's oldest ballpark (1912); take a tour or catch a game.
Why now Our curated notes say it's best Apr–Sep.
Boston Public Garden
Victorian garden with the swan boats and lagoon next to the Common.
Why now September scores 83/100 for comfort, good conditions for being outside.
Warren Tavern
Charlestown tavern from 1780 near the end of the Freedom Trail.
Why now Highs near 75°F and 3.6 in of monthly rain make this an easy outdoor pick.
Freedom Trail
2.5-mile red-brick line past 16 Revolutionary-era sites.
Why now One to do outside while the weather is on your side.
Union Oyster House
America's oldest operating restaurant (1826), serving oysters at a raw bar.
Nearby in September
- Portsmouth in September~51 mi · highs 69°F, 3.5 in rain · 4°C (7°F) cooler by day, about as wet
- New Hampshire in September~63 mi · highs 74°F, 3.7 in rain · similar daytime temperatures, about as wet
- Portland, Maine in September~98 mi · highs 65°F, 3.8 in rain · 6°C (10°F) cooler by day, about as wet
- Woodstock in September~114 mi · highs 71°F, 3.6 in rain · 2°C (4°F) cooler by day, about as wet
These averages also cover Downtown Boston & the Waterfront and South Boston & Castle Island.
NASA POWER 2001–2025 monthly averages on a ~50 km grid. Comfort scores weigh temperature, rain, humidity and cloud: see how we score each month. Check a forecast before you go.
Boston in September: quick answers
Is September a good time to visit Boston?
Yes. On the climate data it's one of the best months, scoring 83/100. Expect highs of 75°F (24°C) and 3.6 in (92 mm) of rain. September is inside the May – Oct window our Boston to Portland route recommends.
How hot is Boston in September?
Average highs are 75°F (24°C) and average lows 56°F (13°C), making it the 3rd-warmest month by daytime highs.
Does it rain a lot in Boston in September?
Some: about 3.6 in (92 mm) of rain falls across September on average, the 3rd-driest month of the year. The annual total is about 47.5 in (1207 mm).
What should I pack for Boston in September?
Bring light, breathable clothes (75°F afternoons), packable rain jacket or umbrella (about 3.6 in of rain) and comfortable walking shoes (most places below are best reached on foot or with short walks).
Routes in season in September
- Boston to Portland May – Oct
Planning Boston in September?
Bring the crew into one shared trip: vote on dates, build the day-by-day plan, split costs and share one packing list.