S
M
T
W
T
F
S
30
76°
66°
31
80°
66°
1
81°
67°
2
82°
66°
3
81°
59°
4
80°
57°
5
73°
59°
6
73°
64°
7
75°
64°
8
78°
63°
9
79°
64°
10
78°
62°
11
77°
60°
12
77°
58°
13
76°
63°
14
77°
64°
15
78°
63°
16
78°
57°
17
76°
62°
18
73°
60°
19
76°
57°
20
71°
53°
21
68°
51°
22
68°
57°
23
69°
56°
24
73°
51°
25
67°
50°
26
65°
50°
27
66°
56°
28
70°
57°
29
72°
52°
30
70°
52°
1
63°
55°
2
64°
48°
3
63°
50°
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 63° to 82°, with overnight lows between 48° and 67°. The average high for September is 74° with an average low of 58°. 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.
