S
M
T
W
T
F
S
30
84°
54°
31
83°
51°
1
82°
52°
2
81°
51°
3
80°
49°
4
79°
50°
5
79°
49°
6
80°
53°
7
80°
53°
8
81°
51°
9
80°
50°
10
80°
50°
11
81°
52°
12
79°
55°
13
80°
56°
14
85°
55°
15
85°
55°
16
84°
54°
17
82°
56°
18
84°
56°
19
85°
54°
20
84°
55°
21
84°
54°
22
83°
52°
23
82°
53°
24
81°
54°
25
82°
56°
26
Hist. Avg.
80°
54°
27
Hist. Avg.
79°
54°
28
Hist. Avg.
79°
54°
29
Hist. Avg.
79°
54°
30
Hist. Avg.
79°
53°
1
Hist. Avg.
79°
53°
2
Hist. Avg.
78°
53°
3
Hist. Avg.
78°
53°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Greenbrae
Greenbrae's September 2026 forecast shows daily high temperatures ranging from 79° to 85°, with overnight lows between 49° and 56°. The average high for September is 82° 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 Greenbrae. See also: October | November | December.
