S
M
T
W
T
F
S
30
87°
64°
31
82°
61°
1
82°
62°
2
81°
62°
3
83°
63°
4
77°
58°
5
76°
60°
6
74°
59°
7
80°
59°
8
79°
58°
9
79°
59°
10
81°
60°
11
79°
59°
12
78°
58°
13
76°
58°
14
72°
56°
15
68°
51°
16
67°
55°
17
76°
55°
18
76°
56°
19
77°
56°
20
77°
55°
21
76°
55°
22
77°
52°
23
68°
47°
24
65°
50°
25
69°
52°
26
68°
53°
27
75°
53°
28
75°
52°
29
73°
53°
30
72°
52°
1
72°
51°
2
68°
50°
3
68°
49°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Waterville
Waterville's September 2026 forecast shows daily high temperatures ranging from 65° to 87°, with overnight lows between 47° and 64°. The average high for September is 75° with an average low of 56°. 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 Waterville. See also: October | November | December.