S
M
T
W
T
F
S
30
90°
59°
31
89°
56°
1
85°
51°
2
86°
52°
3
88°
53°
4
86°
55°
5
84°
58°
6
85°
55°
7
84°
54°
8
83°
57°
9
84°
55°
10
86°
55°
11
83°
54°
12
89°
53°
13
87°
55°
14
88°
54°
15
83°
50°
16
81°
52°
17
80°
54°
18
81°
55°
19
82°
54°
20
83°
55°
21
83°
55°
22
85°
56°
23
82°
55°
24
84°
55°
25
86°
56°
26
80°
57°
27
85°
57°
28
86°
56°
29
86°
56°
30
85°
55°
1
86°
55°
2
85°
54°
3
84°
55°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Livermore-Pleasanton
Livermore-Pleasanton's September 2026 forecast shows daily high temperatures ranging from 80° to 90°, with overnight lows between 50° and 59°. The average high for September is 85° with an average low of 55°. 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 Livermore-Pleasanton. See also: October | November | December.
