S
M
T
W
T
F
S
30
71°
67°
31
74°
67°
1
79°
71°
2
82°
69°
3
80°
68°
4
76°
67°
5
76°
67°
6
70°
61°
7
76°
60°
8
74°
63°
9
76°
68°
10
80°
66°
11
72°
62°
12
77°
60°
13
81°
64°
14
71°
60°
15
76°
59°
16
74°
68°
17
73°
67°
18
68°
64°
19
64°
59°
20
67°
59°
21
63°
56°
22
61°
47°
23
66°
45°
24
66°
41°
25
68°
52°
26
72°
55°
27
69°
55°
28
65°
54°
29
71°
58°
30
74°
58°
1
73°
61°
2
74°
59°
3
69°
57°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Niagara Falls
Niagara Falls's September 2026 forecast shows daily high temperatures ranging from 65° to 74°, with overnight lows between 52° and 61°. The average high for September is 71° with an average low of 57°. 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 Niagara Falls. See also: October | November | December.