The month in detail
What to expect in September
Autumn in Boston is often underrated: 23°C, golden light and declining crowds. An interesting window. Rain risk remains low (25% of days), leaving good room for outdoor activities. A good balance between weather and crowds, even if August (8.8/10) remains theoretically better.
September ranks 4 out of 12 months in Boston. Compared to August: −5°C daytime, −1.0h of sun per day.
This month's conditions
What it's like in September
UV index
5 · moderate
protect during midday hours
Feels like
comfortable
14°
Sea
19°C
cool, invigorating
Daylight
12.3h of daylight
Air quality
good
AQI 27
Compare
Is September the right month?
The best month in Boston is August (8.8/10), 0.7 pt higher than September.
Book
Plan your trip
Hotels at their lowest outside peak season, highest on comfortable months. Shoulder seasons offer a good price/climate compromise.
Stay
Hotels & rentals · Boston
Expedia →
Activities
Tours, tickets, experiences
See ↓
Flights
Multi-airline comparator
Kiwi →
🎟️ Activities & tours · Boston
GetYourGuide selection · free cancellation
Practical info
What you need to know before you go
Three angles: the country (language, currency, safety, budget), the year-round climate, and the specifics of a beach holiday.
Country · USA
🗣️LanguageEnglish
💶CurrencyUS Dollar ($)
🚗DrivingRight-hand
🛡️Safety ⓘVery safe · 1/5
💰Cost of living ⓘExpensive · 4/5
🌡️ Climate
🌍Climate typeTemperate oceanic
📈Climate trend ⓘStable
🔥Hottest monthJuly · 29°C
❄️Coolest monthJanuary · 3°C
🌧️Rainiest month ⓘApril · 30%
🏖️ Beach holiday
📅Peak seasonJuin → Sept
🏖️Swell (Sept–Mar) ⓘModérée
Explore
Other destinations in September
If September doesn't convince you for this destination, compare with others.
Similar climate
New YorkUnited States
TorontoCanadaCape CodUnited StatesChicagoUSA
PragueCzech Republic
Location
Where is Boston ?
Global position + regional geographic context.
🌍 World
🔍 Geographic context
USATemperate oceanic climate with a 8.8 → 1.2 gap between best and worst month. 10 years of ERA5 data to choose by project.
42.36°N · 71.06°W
Questions
Frequently asked questions
What is the best time to visit Boston?
August is the best month with 28.0°C highs, 18.0°C lows, 8.9h of sunshine and 25.0% rainy days. The months of August & July offer comparable conditions.
How many hours of sunshine does Boston get in August?
Boston averages 8.9 sunshine hours per day in August. It is the sunniest month with a climate score of 8.3/10.
What is the rainiest month in Boston?
December is the most unfavourable month with December has the lowest climate score of the year and the lowest climate score of the year.
What are the temperatures at night in Boston in August?
In August, overnight lows reach 18.0°C, while afternoon highs average 28.0°C.
Is Boston good in winter?
In winter (December-February), Boston scores 3.0/10 on average — Difficult period — prefer the peak season.. The best month overall remains August with a score of 8.3/10.
When should you avoid Boston?
December is the most difficult month to visit Boston, with December has the lowest climate score of the year. Climate conditions are at their lowest of the year during this period.
Can you swim in Boston in September?
In September, the sea averages 19°C in Boston: cool, invigorating. Swimming is possible but brisk; sensitive swimmers may prefer a wetsuit.
Do you need sun protection in Boston in September?
The average UV index reaches 5 in September in Boston (moderate), with about 12.3h of daylight. Protect during midday hours.