S
M
T
W
T
F
S
30
89°
73°
31
93°
72°
1
94°
73°
2
97°
76°
3
88°
71°
4
88°
70°
5
82°
62°
6
79°
56°
7
79°
55°
8
81°
55°
9
81°
68°
10
78°
56°
11
80°
55°
12
82°
53°
13
67°
42°
14
68°
61°
15
76°
57°
16
68°
61°
17
74°
60°
18
73°
60°
19
72°
55°
20
69°
54°
21
68°
51°
22
71°
53°
23
73°
52°
24
72°
54°
25
72°
48°
26
76°
55°
27
75°
54°
28
74°
53°
29
72°
54°
30
71°
53°
1
73°
52°
2
73°
51°
3
71°
51°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Fontana-on-Geneva Lake
Fontana-on-Geneva Lake's September 2026 forecast shows daily high temperatures ranging from 67° to 82°, with overnight lows between 42° and 61°. The average high for September is 72° with an average low of 54°. 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 Fontana-on-Geneva Lake. See also: October | November | December.
