S
M
T
W
T
F
S
30
85°
49°
31
89°
50°
1
89°
53°
2
85°
48°
3
83°
48°
4
83°
49°
5
84°
51°
6
84°
50°
7
85°
49°
8
84°
51°
9
83°
52°
10
84°
55°
11
85°
54°
12
86°
54°
13
86°
56°
14
89°
56°
15
90°
54°
16
90°
54°
17
89°
53°
18
88°
53°
19
88°
52°
20
86°
53°
21
88°
54°
22
88°
54°
23
87°
53°
24
83°
54°
25
79°
53°
26
78°
52°
27
81°
53°
28
80°
54°
29
81°
53°
30
80°
54°
1
83°
50°
2
80°
50°
3
85°
54°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Sonoma
Sonoma's September 2026 forecast shows daily high temperatures ranging from 78° to 90°, with overnight lows between 48° and 56°. The average high for September is 85° 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 Sonoma. See also: October | November | December.
