S
M
T
W
T
F
S
30
93°
60°
31
93°
60°
1
94°
59°
2
92°
59°
3
92°
60°
4
91°
59°
5
91°
60°
6
92°
61°
7
92°
62°
8
91°
60°
9
90°
62°
10
90°
63°
11
93°
62°
12
95°
62°
13
94°
63°
14
94°
65°
15
95°
64°
16
93°
64°
17
95°
63°
18
95°
62°
19
94°
63°
20
94°
65°
21
93°
65°
22
95°
64°
23
95°
64°
24
93°
61°
25
86°
58°
26
84°
58°
27
85°
60°
28
84°
61°
29
88°
59°
30
84°
57°
1
81°
58°
2
82°
60°
3
82°
60°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Fontana
Fontana's September 2026 forecast shows daily high temperatures ranging from 81° to 95°, with overnight lows between 57° and 65°. The average high for September is 91° with an average low of 61°. 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. See also: October | November | December.
