S
M
T
W
T
F
S
26
76°
55°
27
77°
53°
28
85°
54°
29
81°
56°
30
84°
56°
31
89°
55°
1
89°
56°
2
91°
57°
3
86°
56°
4
79°
59°
5
78°
61°
6
78°
59°
7
78°
59°
8
75°
60°
9
84°
61°
10
83°
53°
11
81°
57°
12
84°
60°
13
74°
58°
14
75°
60°
15
75°
58°
16
78°
58°
17
77°
58°
18
77°
58°
19
76°
59°
20
76°
60°
21
79°
59°
22
85°
55°
23
87°
56°
24
80°
57°
25
81°
57°
26
88°
62°
27
84°
60°
28
77°
55°
29
74°
55°
30
85°
52°
31
83°
53°
1
87°
53°
2
88°
52°
3
88°
52°
4
89°
53°
5
88°
54°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Portola Valley
Portola Valley's August 2026 forecast shows daily high temperatures ranging from 74° to 89°, with overnight lows between 52° and 62°. The average high for August is 84° with an average low of 55°. 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 Portola Valley. See also: September | October | November.
