S
M
T
W
T
F
S
30
63°
38°
31
65°
41°
1
69°
43°
2
65°
42°
3
64°
41°
4
63°
36°
5
67°
44°
6
70°
45°
7
Hist. Avg.
66°
39°
8
Hist. Avg.
66°
38°
9
Hist. Avg.
65°
38°
10
Hist. Avg.
65°
38°
11
Hist. Avg.
65°
38°
12
Hist. Avg.
64°
37°
13
Hist. Avg.
64°
37°
14
Hist. Avg.
64°
37°
15
Hist. Avg.
64°
36°
16
Hist. Avg.
63°
36°
17
Hist. Avg.
63°
36°
18
Hist. Avg.
63°
36°
19
Hist. Avg.
62°
35°
20
Hist. Avg.
62°
35°
21
Hist. Avg.
62°
35°
22
Hist. Avg.
61°
34°
23
Hist. Avg.
61°
34°
24
Hist. Avg.
61°
34°
25
Hist. Avg.
60°
33°
26
Hist. Avg.
60°
33°
27
Hist. Avg.
60°
33°
28
Hist. Avg.
59°
32°
29
Hist. Avg.
59°
32°
30
Hist. Avg.
59°
32°
1
Hist. Avg.
58°
31°
2
Hist. Avg.
58°
31°
3
Hist. Avg.
58°
31°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Half Moon Bay
Half Moon Bay's September 2026 forecast shows daily high temperatures ranging from 63° to 70°, with overnight lows between 36° and 45°. The average high for September is 66° with an average low of 41°. 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 Half Moon Bay. See also: October | November | December.
