S
M
T
W
T
F
S
30
82°
66°
31
90°
71°
1
91°
73°
2
93°
73°
3
92°
73°
4
91°
71°
5
85°
68°
6
82°
60°
7
82°
55°
8
85°
55°
9
80°
67°
10
76°
56°
11
79°
64°
12
85°
66°
13
75°
59°
14
76°
72°
15
84°
62°
16
70°
64°
17
70°
58°
18
71°
55°
19
71°
55°
20
70°
55°
21
68°
53°
22
69°
56°
23
72°
54°
24
76°
58°
25
70°
58°
26
76°
59°
27
76°
59°
28
75°
58°
29
74°
59°
30
74°
56°
1
71°
54°
2
67°
56°
3
71°
56°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Indiana Dunes State Park
Indiana Dunes State Park's September 2026 forecast shows daily high temperatures ranging from 67° to 85°, with overnight lows between 53° and 72°. The average high for September is 74° with an average low of 58°. 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 Indiana Dunes State Park. See also: October | November | December.
