S
M
T
W
T
F
S
30
80°
54°
31
70°
53°
1
70°
58°
2
73°
60°
3
72°
57°
4
75°
56°
5
75°
55°
6
84°
54°
7
92°
55°
8
91°
60°
9
93°
59°
10
93°
59°
11
92°
59°
12
87°
58°
13
86°
59°
14
87°
56°
15
85°
58°
16
81°
57°
17
87°
58°
18
86°
56°
19
80°
54°
20
82°
59°
21
83°
56°
22
86°
56°
23
80°
57°
24
78°
53°
25
79°
54°
26
78°
53°
27
77°
52°
28
78°
53°
29
79°
54°
30
78°
56°
1
77°
52°
2
78°
54°
3
84°
58°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Vallejo
Vallejo's September 2026 forecast shows daily high temperatures ranging from 70° to 93°, with overnight lows between 52° and 60°. The average high for September is 82° with an average low of 56°. 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 Vallejo. See also: October | November | December.
