S
M
T
W
T
F
S
30
93°
58°
31
97°
66°
1
99°
67°
2
99°
69°
3
99°
69°
4
100°
69°
5
100°
71°
6
88°
64°
7
86°
57°
8
94°
55°
9
93°
70°
10
79°
69°
11
86°
67°
12
91°
65°
13
89°
62°
14
85°
57°
15
99°
61°
16
95°
69°
17
100°
66°
18
96°
70°
19
93°
67°
20
91°
68°
21
73°
60°
22
69°
58°
23
69°
60°
24
73°
61°
25
78°
55°
26
76°
46°
27
76°
46°
28
78°
50°
29
78°
57°
30
79°
64°
1
80°
65°
2
79°
62°
3
76°
59°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Sullivan
Sullivan's September 2026 forecast shows daily high temperatures ranging from 76° to 80°, with overnight lows between 46° and 65°. The average high for September is 78° with an average low of 56°. 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 Sullivan. See also: October | November | December.
