S
M
T
W
T
F
S
30
72°
65°
31
74°
60°
1
78°
64°
2
84°
67°
3
79°
65°
4
76°
60°
5
75°
59°
6
72°
54°
7
76°
53°
8
77°
63°
9
74°
65°
10
74°
51°
11
68°
49°
12
77°
64°
13
77°
57°
14
69°
57°
15
72°
58°
16
69°
54°
17
71°
52°
18
62°
50°
19
60°
49°
20
62°
50°
21
61°
38°
22
65°
53°
23
68°
54°
24
69°
53°
25
71°
53°
26
71°
50°
27
64°
47°
28
70°
52°
29
71°
53°
30
72°
54°
1
72°
53°
2
70°
51°
3
69°
49°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Black River
Black River's September 2026 forecast shows daily high temperatures ranging from 60° to 77°, with overnight lows between 38° and 65°. The average high for September is 69° with an average low of 53°. 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 Black River. See also: October | November | December.