S
M
T
W
T
F
S
30
64°
59°
31
79°
55°
1
79°
54°
2
75°
54°
3
72°
55°
4
64°
55°
5
70°
55°
6
73°
52°
7
73°
57°
8
72°
61°
9
70°
52°
10
72°
48°
11
76°
54°
12
67°
42°
13
62°
41°
14
56°
50°
15
67°
44°
16
62°
44°
17
66°
43°
18
65°
47°
19
64°
43°
20
64°
47°
21
66°
47°
22
66°
51°
23
65°
47°
24
63°
41°
25
67°
49°
26
68°
48°
27
67°
49°
28
67°
49°
29
64°
48°
30
64°
46°
1
59°
46°
2
60°
45°
3
58°
45°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Knife River
Knife River's September 2026 forecast shows daily high temperatures ranging from 56° to 76°, with overnight lows between 41° and 54°. The average high for September is 64° with an average low of 46°. 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 Knife River. See also: October | November | December.
