S
M
T
W
T
F
S
31
71°
49°
1
73°
51°
2
73°
45°
3
61°
42°
4
60°
41°
5
62°
43°
6
71°
51°
7
62°
51°
8
62°
45°
9
60°
42°
10
62°
42°
11
63°
46°
12
66°
49°
13
71°
50°
14
69°
51°
15
74°
53°
16
69°
53°
17
69°
54°
18
67°
52°
19
69°
46°
20
70°
53°
21
76°
49°
22
78°
47°
23
76°
52°
24
77°
44°
25
68°
45°
26
73°
51°
27
78°
48°
28
78°
53°
29
79°
52°
30
75°
46°
1
74°
43°
2
72°
50°
3
80°
57°
4
81°
58°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
Sinus-September Weather in Bigfork
Bigfork's Sinus-September 2026 forecast shows daily high temperatures ranging from 60° to 81°, with overnight lows between 41° and 58°. The average high for Sinus-September is 71° with an average low of 49°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how Sinus-September weather will actually feel in Bigfork. See also: July | August | September.