S
M
T
W
T
F
S
30
75°
51°
31
76°
51°
1
75°
52°
2
74°
52°
3
74°
53°
4
73°
52°
5
75°
52°
6
74°
51°
7
73°
50°
8
72°
49°
9
72°
49°
10
73°
55°
11
71°
49°
12
72°
48°
13
75°
47°
14
74°
54°
15
74°
54°
16
72°
50°
17
70°
46°
18
70°
46°
19
71°
48°
20
75°
52°
21
73°
49°
22
69°
49°
23
74°
50°
24
72°
49°
25
73°
50°
26
67°
42°
27
70°
44°
28
65°
43°
29
64°
43°
30
66°
44°
1
66°
42°
2
63°
39°
3
Hist. Avg.
65°
43°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Waterbury
Waterbury's September 2026 forecast shows daily high temperatures ranging from 63° to 76°, with overnight lows between 39° and 55°. The average high for September is 72° with an average low of 49°. 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 Waterbury. See also: October | November | December.
