S
M
T
W
T
F
S
30
96°
73°
31
98°
71°
1
99°
71°
2
99°
75°
3
97°
72°
4
91°
69°
5
91°
71°
6
90°
70°
7
91°
73°
8
90°
69°
9
90°
70°
10
92°
69°
11
89°
76°
12
93°
76°
13
97°
75°
14
98°
73°
15
96°
74°
16
95°
73°
17
96°
75°
18
96°
69°
19
87°
68°
20
87°
72°
21
91°
73°
22
95°
75°
23
94°
68°
24
85°
69°
25
90°
67°
26
90°
67°
27
91°
70°
28
90°
67°
29
83°
67°
30
85°
66°
1
82°
65°
2
81°
66°
3
85°
66°
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 81° to 99°, with overnight lows between 65° and 76°. The average high for September is 91° with an average low of 71°. 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.
