S
M
T
W
T
F
S
30
81°
61°
31
79°
60°
1
80°
55°
2
73°
53°
3
72°
55°
4
72°
53°
5
73°
52°
6
75°
59°
7
79°
59°
8
73°
58°
9
72°
58°
10
76°
57°
11
78°
57°
12
77°
58°
13
78°
59°
14
78°
48°
15
70°
48°
16
68°
49°
17
70°
48°
18
69°
46°
19
68°
47°
20
68°
50°
21
75°
52°
22
75°
53°
23
74°
46°
24
75°
44°
25
69°
44°
26
67°
46°
27
72°
51°
28
72°
51°
29
73°
43°
30
71°
43°
1
65°
44°
2
66°
45°
3
69°
48°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Southborough
Southborough's September 2026 forecast shows daily high temperatures ranging from 65° to 81°, with overnight lows between 43° and 61°. The average high for September is 73° with an average low of 51°. 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 Southborough. See also: October | November | December.
