S
M
T
W
T
F
S
30
77°
41°
31
77°
41°
1
83°
46°
2
85°
49°
3
87°
49°
4
87°
47°
5
75°
39°
6
74°
44°
7
77°
44°
8
76°
47°
9
79°
46°
10
77°
40°
11
75°
42°
12
75°
45°
13
74°
43°
14
72°
37°
15
70°
36°
16
69°
34°
17
69°
36°
18
70°
37°
19
69°
41°
20
74°
41°
21
77°
38°
22
68°
36°
23
67°
35°
24
66°
34°
25
64°
35°
26
65°
36°
27
63°
34°
28
64°
37°
29
70°
37°
30
71°
34°
1
Hist. Avg.
67°
43°
2
Hist. Avg.
66°
43°
3
Hist. Avg.
66°
43°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Thompson Falls
Thompson Falls's September 2026 forecast shows daily high temperatures ranging from 63° to 87°, with overnight lows between 34° and 49°. The average high for September is 73° with an average low of 40°. 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 Thompson Falls. See also: October | November | December.
