S
M
T
W
T
F
S
30
90°
66°
31
88°
66°
1
89°
68°
2
90°
65°
3
86°
64°
4
85°
65°
5
85°
64°
6
89°
67°
7
89°
68°
8
88°
67°
9
88°
68°
10
87°
67°
11
88°
67°
12
87°
66°
13
88°
67°
14
87°
65°
15
84°
65°
16
86°
64°
17
86°
60°
18
82°
61°
19
83°
62°
20
84°
64°
21
85°
63°
22
81°
62°
23
85°
62°
24
83°
63°
25
83°
61°
26
83°
61°
27
79°
62°
28
Hist. Avg.
80°
58°
29
Hist. Avg.
80°
57°
30
Hist. Avg.
79°
57°
1
Hist. Avg.
79°
56°
2
Hist. Avg.
79°
56°
3
Hist. Avg.
78°
56°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Sumter Southeast
Sumter Southeast's September 2026 forecast shows daily high temperatures ranging from 79° to 90°, with overnight lows between 60° and 68°. The average high for September is 86° with an average low of 64°. 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 Sumter Southeast. See also: October | November | December.
