S
M
T
W
T
F
S
30
72°
53°
31
75°
54°
1
75°
55°
2
70°
53°
3
75°
54°
4
79°
54°
5
79°
55°
6
78°
54°
7
73°
50°
8
76°
52°
9
76°
53°
10
69°
51°
11
68°
47°
12
67°
49°
13
67°
45°
14
66°
43°
15
69°
44°
16
73°
47°
17
70°
52°
18
65°
52°
19
65°
51°
20
67°
51°
21
66°
41°
22
68°
49°
23
68°
49°
24
71°
45°
25
74°
50°
26
72°
41°
27
62°
40°
28
59°
38°
29
60°
40°
30
59°
47°
1
60°
44°
2
60°
40°
3
63°
49°
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 59° to 79°, with overnight lows between 38° and 55°. The average high for September is 69° with an average low of 48°. 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.
