S
M
T
W
T
F
S
30
74°
61°
31
68°
51°
1
68°
55°
2
70°
56°
3
68°
56°
4
67°
54°
5
69°
51°
6
67°
52°
7
72°
55°
8
74°
56°
9
73°
56°
10
74°
55°
11
72°
54°
12
73°
55°
13
74°
54°
14
74°
51°
15
64°
50°
16
64°
51°
17
65°
51°
18
68°
52°
19
69°
51°
20
65°
48°
21
62°
48°
22
64°
50°
23
70°
51°
24
70°
50°
25
69°
51°
26
70°
51°
27
70°
50°
28
61°
50°
29
65°
47°
30
68°
45°
1
59°
44°
2
57°
38°
3
61°
32°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Waterloo Airport
Waterloo Airport's September 2026 forecast shows daily high temperatures ranging from 57° to 74°, with overnight lows between 32° and 61°. The average high for September is 68° with an average low of 51°. 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 Waterloo Airport. See also: October | November | December.
