S
M
T
W
T
F
S
30
84°
57°
31
86°
60°
1
88°
57°
2
81°
56°
3
80°
63°
4
86°
62°
5
85°
62°
6
87°
55°
7
80°
57°
8
80°
61°
9
79°
60°
10
85°
60°
11
81°
59°
12
84°
57°
13
78°
52°
14
76°
51°
15
76°
52°
16
77°
52°
17
77°
56°
18
82°
59°
19
82°
57°
20
80°
58°
21
81°
57°
22
82°
58°
23
80°
49°
24
81°
48°
25
73°
47°
26
73°
49°
27
74°
47°
28
Hist. Avg.
75°
52°
29
Hist. Avg.
75°
51°
30
Hist. Avg.
75°
51°
1
Hist. Avg.
74°
51°
2
Hist. Avg.
74°
50°
3
Hist. Avg.
74°
50°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Sullivan
Sullivan's September 2026 forecast shows daily high temperatures ranging from 73° to 88°, with overnight lows between 47° and 63°. The average high for September is 81° 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.
