S
M
T
W
T
F
S
30
86°
65°
31
73°
63°
1
69°
63°
2
72°
63°
3
77°
66°
4
81°
61°
5
71°
59°
6
69°
55°
7
75°
62°
8
79°
62°
9
72°
64°
10
78°
63°
11
72°
59°
12
73°
60°
13
74°
62°
14
70°
61°
15
72°
58°
16
72°
62°
17
76°
61°
18
68°
56°
19
73°
61°
20
72°
60°
21
70°
58°
22
70°
60°
23
71°
60°
24
72°
59°
25
68°
58°
26
71°
60°
27
73°
61°
28
73°
57°
29
66°
54°
30
66°
56°
1
66°
54°
2
63°
56°
3
62°
55°
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 62° to 81°, with overnight lows between 54° and 66°. The average high for September is 71° with an average low of 59°. 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.
