S
M
T
W
T
F
S
30
90°
69°
31
91°
71°
1
92°
69°
2
91°
68°
3
90°
68°
4
90°
69°
5
89°
67°
6
89°
67°
7
90°
68°
8
90°
67°
9
91°
67°
10
88°
66°
11
88°
69°
12
89°
67°
13
91°
68°
14
86°
67°
15
86°
64°
16
85°
65°
17
87°
68°
18
89°
69°
19
90°
70°
20
92°
70°
21
91°
75°
22
91°
68°
23
90°
69°
24
89°
69°
25
90°
70°
26
91°
69°
27
92°
72°
28
93°
70°
29
86°
68°
30
87°
67°
1
87°
66°
2
83°
62°
3
80°
59°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Boulder City
Boulder City's September 2026 forecast shows daily high temperatures ranging from 80° to 93°, with overnight lows between 59° and 75°. The average high for September is 89° with an average low of 68°. 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 Boulder City. See also: October | November | December.
