S
M
T
W
T
F
S
30
86°
65°
31
73°
63°
1
69°
63°
2
72°
64°
3
73°
63°
4
85°
66°
5
73°
64°
6
68°
59°
7
82°
59°
8
81°
64°
9
76°
61°
10
87°
71°
11
79°
63°
12
71°
56°
13
70°
63°
14
74°
58°
15
66°
53°
16
80°
56°
17
76°
64°
18
80°
62°
19
62°
54°
20
63°
55°
21
65°
55°
22
63°
53°
23
64°
51°
24
65°
49°
25
64°
50°
26
61°
55°
27
60°
56°
28
58°
56°
29
66°
56°
30
66°
60°
1
75°
64°
2
83°
56°
3
68°
47°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Brookline
Brookline's September 2026 forecast shows daily high temperatures ranging from 68° to 83°, with overnight lows between 47° and 64°. The average high for September is 75° 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 Brookline. See also: October | November | December.
