S
M
T
W
T
F
S
30
64°
55°
31
65°
54°
1
64°
55°
2
67°
55°
3
68°
54°
4
65°
53°
5
63°
50°
6
65°
49°
7
64°
50°
8
65°
55°
9
64°
49°
10
66°
50°
11
67°
50°
12
65°
50°
13
65°
55°
14
69°
55°
15
Hist. Avg.
66°
51°
16
Hist. Avg.
66°
51°
17
Hist. Avg.
66°
51°
18
Hist. Avg.
66°
51°
19
Hist. Avg.
66°
51°
20
Hist. Avg.
66°
51°
21
Hist. Avg.
66°
51°
22
Hist. Avg.
67°
51°
23
Hist. Avg.
67°
50°
24
Hist. Avg.
67°
50°
25
Hist. Avg.
67°
50°
26
Hist. Avg.
67°
50°
27
Hist. Avg.
67°
50°
28
Hist. Avg.
67°
50°
29
Hist. Avg.
67°
50°
30
Hist. Avg.
67°
50°
1
Hist. Avg.
67°
50°
2
Hist. Avg.
67°
49°
3
Hist. Avg.
67°
49°
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 69°, with overnight lows between 49° and 55°. The average high for September is 65° with an average low of 52°. 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.
