S
M
T
W
T
F
S
30
82°
66°
31
87°
66°
1
90°
73°
2
95°
73°
3
95°
70°
4
87°
68°
5
81°
67°
6
78°
58°
7
79°
57°
8
84°
55°
9
81°
66°
10
80°
59°
11
79°
55°
12
83°
61°
13
79°
55°
14
71°
44°
15
90°
55°
16
80°
69°
17
80°
68°
18
76°
61°
19
67°
60°
20
66°
57°
21
63°
52°
22
62°
49°
23
62°
55°
24
70°
50°
25
69°
44°
26
N/A
27
74°
42°
28
74°
49°
29
77°
47°
30
69°
54°
1
86°
63°
2
65°
50°
3
N/A
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Waterloo
Waterloo's September 2026 forecast shows daily high temperatures ranging from ° to °, with overnight lows between ° and °. The average high for September is ° with an average low of °. 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. See also: October | November | December.
