S
M
T
W
T
F
S
26
98°
73°
27
96°
72°
28
93°
70°
29
92°
66°
30
94°
65°
31
100°
69°
1
99°
72°
2
98°
73°
3
96°
70°
4
92°
69°
5
92°
67°
6
95°
69°
7
95°
72°
8
99°
73°
9
97°
75°
10
94°
74°
11
93°
72°
12
88°
68°
13
84°
66°
14
86°
64°
15
88°
64°
16
91°
66°
17
95°
69°
18
96°
72°
19
100°
72°
20
98°
73°
21
99°
77°
22
99°
74°
23
101°
76°
24
102°
73°
25
104°
77°
26
107°
78°
27
106°
78°
28
107°
77°
29
104°
72°
30
101°
65°
31
102°
68°
1
100°
66°
2
101°
67°
3
100°
67°
4
97°
65°
5
98°
66°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Fontana
Fontana's August 2026 forecast shows daily high temperatures ranging from 97° to 107°, with overnight lows between 65° and 78°. The average high for August is 102° with an average low of 71°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how August weather will actually feel in Fontana. See also: September | October | November.
