S
M
T
W
T
F
S
30
80°
65°
31
75°
59°
1
73°
61°
2
73°
59°
3
72°
59°
4
72°
62°
5
73°
65°
6
75°
66°
7
77°
65°
8
79°
63°
9
78°
62°
10
73°
65°
11
78°
64°
12
80°
63°
13
77°
64°
14
76°
63°
15
79°
55°
16
76°
54°
17
68°
53°
18
68°
57°
19
70°
58°
20
71°
61°
21
74°
60°
22
70°
60°
23
74°
61°
24
75°
59°
25
72°
60°
26
74°
60°
27
75°
53°
28
74°
50°
29
73°
50°
30
62°
55°
1
63°
49°
2
65°
54°
3
63°
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 80°, with overnight lows between 49° and 66°. The average high for September is 73° 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.
