S
M
T
W
T
F
S
26
64°
53°
27
65°
52°
28
71°
45°
29
76°
47°
30
74°
46°
1
70°
50°
2
65°
54°
3
64°
54°
4
67°
50°
5
64°
52°
6
74°
52°
7
68°
54°
8
69°
52°
9
74°
50°
10
75°
49°
11
80°
52°
12
74°
55°
13
68°
54°
14
80°
48°
15
80°
49°
16
70°
51°
17
74°
48°
18
82°
63°
19
87°
50°
20
88°
52°
21
84°
53°
22
74°
54°
23
77°
52°
24
76°
52°
25
68°
52°
26
64°
53°
27
68°
53°
28
71°
51°
29
66°
52°
30
67°
49°
31
79°
46°
1
81°
50°
2
82°
50°
3
83°
51°
4
83°
52°
5
80°
49°
6
78°
51°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Portola Valley
Portola Valley's May 2026 forecast shows daily high temperatures ranging from 66° to 83°, with overnight lows between 46° and 53°. The average high for May is 76° with an average low of 50°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how May weather will actually feel in Portola Valley. See also: June | July | August.
