S
M
T
W
T
F
S
30
65°
59°
31
64°
58°
1
66°
57°
2
69°
54°
3
69°
56°
4
68°
52°
5
67°
50°
6
67°
55°
7
65°
53°
8
68°
50°
9
83°
56°
10
83°
60°
11
67°
60°
12
65°
52°
13
67°
60°
14
76°
56°
15
63°
56°
16
63°
56°
17
67°
57°
18
68°
58°
19
65°
54°
20
61°
53°
21
63°
55°
22
66°
54°
23
66°
55°
24
67°
54°
25
68°
54°
26
71°
55°
27
63°
49°
28
62°
47°
29
63°
50°
30
64°
50°
1
69°
52°
2
64°
52°
3
65°
50°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Half Moon Bay
Half Moon Bay's September 2026 forecast shows daily high temperatures ranging from 61° to 76°, with overnight lows between 47° and 58°. The average high for September is 66° with an average low of 53°. 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.
