S
M
T
W
T
F
S
30
100°
74°
31
100°
79°
1
103°
78°
2
103°
78°
3
102°
77°
4
104°
77°
5
104°
76°
6
103°
77°
7
100°
73°
8
97°
71°
9
97°
71°
10
96°
70°
11
95°
72°
12
96°
75°
13
98°
74°
14
97°
73°
15
97°
71°
16
99°
71°
17
97°
70°
18
96°
69°
19
Hist. Avg.
95°
71°
20
Hist. Avg.
95°
70°
21
Hist. Avg.
94°
70°
22
Hist. Avg.
94°
70°
23
Hist. Avg.
94°
69°
24
Hist. Avg.
94°
69°
25
Hist. Avg.
93°
69°
26
Hist. Avg.
93°
68°
27
Hist. Avg.
93°
68°
28
Hist. Avg.
92°
68°
29
Hist. Avg.
92°
67°
30
Hist. Avg.
92°
67°
1
Hist. Avg.
91°
67°
2
Hist. Avg.
91°
66°
3
Hist. Avg.
91°
66°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Santa Rosa
Santa Rosa's September 2026 forecast shows daily high temperatures ranging from 95° to 104°, with overnight lows between 69° and 79°. The average high for September is 99° with an average low of 74°. 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 Santa Rosa. See also: October | November | December.
