S
M
T
W
T
F
S
30
74°
55°
31
75°
55°
1
71°
54°
2
73°
51°
3
66°
48°
4
68°
50°
5
71°
53°
6
74°
54°
7
74°
51°
8
69°
47°
9
63°
46°
10
68°
46°
11
61°
37°
12
62°
44°
13
60°
43°
14
62°
41°
15
61°
39°
16
62°
40°
17
60°
39°
18
59°
40°
19
58°
35°
20
57°
36°
21
60°
42°
22
64°
48°
23
68°
39°
24
69°
49°
25
69°
47°
26
71°
46°
27
70°
35°
28
66°
44°
29
58°
37°
30
56°
44°
1
55°
45°
2
66°
32°
3
67°
31°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Mattawa
Mattawa's September 2026 forecast shows daily high temperatures ranging from 55° to 75°, with overnight lows between 31° and 55°. The average high for September is 65° with an average low of 44°. 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 Mattawa. See also: October | November | December.
