S
M
T
W
T
F
S
30
86°
65°
31
73°
63°
1
68°
61°
2
73°
62°
3
76°
63°
4
83°
61°
5
75°
56°
6
72°
55°
7
77°
59°
8
76°
56°
9
74°
57°
10
77°
60°
11
76°
58°
12
78°
57°
13
76°
55°
14
75°
56°
15
72°
58°
16
74°
59°
17
78°
58°
18
70°
55°
19
71°
56°
20
72°
58°
21
76°
58°
22
78°
59°
23
78°
58°
24
77°
57°
25
76°
56°
26
77°
56°
27
76°
57°
28
76°
55°
29
75°
54°
30
68°
49°
1
65°
50°
2
65°
53°
3
72°
53°
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 65° to 83°, with overnight lows between 49° and 63°. The average high for September is 74° with an average low of 57°. 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.
