S
M
T
W
T
F
S
30
93°
71°
31
92°
71°
1
92°
70°
2
91°
71°
3
91°
71°
4
89°
67°
5
90°
70°
6
91°
71°
7
92°
70°
8
91°
69°
9
90°
70°
10
91°
70°
11
90°
69°
12
89°
68°
13
88°
69°
14
88°
69°
15
86°
68°
16
86°
68°
17
85°
67°
18
85°
67°
19
86°
66°
20
85°
62°
21
83°
62°
22
84°
64°
23
87°
66°
24
86°
64°
25
87°
65°
26
86°
66°
27
87°
66°
28
83°
64°
29
82°
63°
30
86°
63°
1
Hist. Avg.
84°
62°
2
Hist. Avg.
84°
62°
3
Hist. Avg.
83°
61°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Boston
Boston's September 2026 forecast shows daily high temperatures ranging from 82° to 93°, with overnight lows between 62° and 71°. The average high for September is 88° with an average low of 67°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how September weather will actually feel in Boston. See also: October | November | December.
