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
67°
50°
15
63°
57°
16
66°
58°
17
68°
57°
18
68°
58°
19
67°
56°
20
64°
57°
21
63°
53°
22
68°
52°
23
71°
55°
24
69°
54°
25
69°
55°
26
66°
54°
27
67°
55°
28
68°
53°
29
67°
50°
30
64°
50°
1
69°
52°
2
63°
52°
3
69°
49°
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 63° to 71°, with overnight lows between 49° and 58°. The average high for September is 67° with an average low of 54°. 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.
