S
M
T
W
T
F
S
30
87°
78°
31
86°
77°
1
87°
78°
2
88°
78°
3
88°
77°
4
87°
79°
5
86°
79°
6
87°
77°
7
88°
78°
8
87°
77°
9
88°
78°
10
87°
78°
11
87°
77°
12
86°
77°
13
86°
76°
14
87°
77°
15
86°
77°
16
87°
76°
17
87°
78°
18
88°
78°
19
88°
77°
20
87°
78°
21
87°
78°
22
86°
77°
23
88°
77°
24
87°
78°
25
88°
77°
26
87°
76°
27
87°
78°
28
86°
77°
29
88°
77°
30
88°
78°
1
Hist. Avg.
86°
77°
2
Hist. Avg.
86°
77°
3
Hist. Avg.
86°
77°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in San Jose
San Jose's September 2026 forecast shows daily high temperatures ranging from 86° to 88°, with overnight lows between 76° and 79°. The average high for September is 87° with an average low of 77°. 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 San Jose. See also: October | November | December.
