S
M
T
W
T
F
S
30
86°
63°
31
85°
62°
1
85°
64°
2
86°
62°
3
88°
66°
4
89°
63°
5
89°
66°
6
88°
63°
7
86°
65°
8
88°
64°
9
87°
65°
10
82°
63°
11
87°
62°
12
87°
64°
13
86°
63°
14
86°
63°
15
85°
62°
16
86°
63°
17
86°
61°
18
85°
60°
19
84°
61°
20
84°
55°
21
80°
59°
22
79°
60°
23
84°
59°
24
84°
58°
25
83°
57°
26
83°
57°
27
82°
58°
28
82°
58°
29
81°
57°
30
82°
55°
1
80°
56°
2
82°
57°
3
82°
57°
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 79° to 89°, with overnight lows between 55° and 66°. The average high for September is 85° with an average low of 61°. 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.
