S
M
T
W
T
F
S
30
68°
56°
31
71°
54°
1
70°
54°
2
70°
55°
3
65°
54°
4
68°
53°
5
69°
52°
6
69°
52°
7
67°
55°
8
71°
52°
9
75°
53°
10
69°
55°
11
66°
54°
12
65°
52°
13
60°
54°
14
63°
54°
15
66°
54°
16
70°
51°
17
72°
54°
18
68°
52°
19
63°
52°
20
66°
50°
21
67°
51°
22
67°
54°
23
61°
51°
24
57°
50°
25
62°
47°
26
61°
46°
27
61°
45°
28
68°
54°
29
63°
47°
30
68°
53°
1
73°
54°
2
70°
53°
3
67°
46°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Index
Index's September 2026 forecast shows daily high temperatures ranging from 63° to 73°, with overnight lows between 46° and 54°. The average high for September is 68° 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 Index. See also: October | November | December.
