S
M
T
W
T
F
S
30
77°
59°
31
73°
56°
1
72°
58°
2
72°
57°
3
73°
59°
4
75°
62°
5
80°
63°
6
79°
63°
7
77°
58°
8
79°
57°
9
72°
62°
10
79°
57°
11
81°
56°
12
74°
61°
13
79°
58°
14
80°
49°
15
74°
46°
16
66°
45°
17
67°
48°
18
68°
55°
19
69°
57°
20
70°
57°
21
72°
56°
22
76°
56°
23
75°
57°
24
75°
57°
25
77°
56°
26
77°
57°
27
75°
44°
28
76°
42°
29
63°
46°
30
62°
44°
1
61°
44°
2
62°
47°
3
62°
43°
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 61° to 81°, with overnight lows between 42° and 63°. The average high for September is 73° with an average low of 54°. 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.