S
M
T
W
T
F
S
30
89°
74°
31
95°
71°
1
98°
73°
2
98°
74°
3
98°
73°
4
97°
72°
5
102°
72°
6
95°
70°
7
89°
72°
8
90°
69°
9
91°
68°
10
94°
72°
11
96°
74°
12
91°
73°
13
93°
74°
14
97°
71°
15
90°
75°
16
90°
68°
17
92°
63°
18
96°
67°
19
91°
72°
20
92°
73°
21
94°
70°
22
89°
72°
23
73°
65°
24
65°
61°
25
77°
52°
26
80°
46°
27
83°
53°
28
85°
56°
29
87°
62°
30
87°
61°
1
89°
57°
2
88°
64°
3
88°
63°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Irmo
Irmo's September 2026 forecast shows daily high temperatures ranging from 83° to 89°, with overnight lows between 53° and 64°. The average high for September is 87° with an average low of 59°. 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 Irmo. See also: October | November | December.
