S
M
T
W
T
F
S
30
88°
73°
31
N/A
1
93°
71°
2
91°
73°
3
91°
74°
4
92°
74°
5
94°
72°
6
91°
70°
7
89°
68°
8
92°
70°
9
94°
68°
10
92°
69°
11
89°
67°
12
89°
67°
13
88°
66°
14
89°
69°
15
89°
68°
16
88°
69°
17
85°
68°
18
84°
68°
19
86°
67°
20
83°
67°
21
86°
66°
22
83°
67°
23
84°
67°
24
86°
66°
25
87°
67°
26
83°
65°
27
82°
66°
28
83°
66°
29
81°
65°
30
81°
65°
1
82°
64°
2
81°
65°
3
80°
64°
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 80° to 94°, with overnight lows between 64° and 74°. The average high for September is 87° with an average low of 68°. 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.
