S
M
T
W
T
F
S
30
82°
59°
31
77°
55°
1
76°
55°
2
76°
56°
3
75°
56°
4
76°
57°
5
75°
56°
6
74°
56°
7
73°
61°
8
75°
58°
9
73°
55°
10
73°
54°
11
72°
54°
12
73°
55°
13
72°
56°
14
71°
55°
15
72°
58°
16
71°
53°
17
73°
52°
18
73°
54°
19
77°
54°
20
Hist. Avg.
73°
54°
21
Hist. Avg.
73°
54°
22
Hist. Avg.
73°
54°
23
Hist. Avg.
72°
54°
24
Hist. Avg.
72°
53°
25
Hist. Avg.
72°
53°
26
Hist. Avg.
71°
52°
27
Hist. Avg.
71°
52°
28
Hist. Avg.
70°
52°
29
Hist. Avg.
70°
51°
30
Hist. Avg.
70°
51°
1
Hist. Avg.
69°
50°
2
Hist. Avg.
69°
50°
3
Hist. Avg.
68°
50°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Boston
Boston's September 2026 forecast shows daily high temperatures ranging from 71° to 82°, with overnight lows between 52° and 61°. The average high for September is 74° with an average low of 56°. 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.