S
M
T
W
T
F
S
30
81°
58°
31
83°
64°
1
89°
67°
2
91°
69°
3
91°
64°
4
80°
56°
5
79°
58°
6
80°
63°
7
81°
61°
8
84°
63°
9
82°
60°
10
82°
56°
11
79°
59°
12
80°
62°
13
78°
54°
14
76°
52°
15
74°
52°
16
75°
51°
17
75°
52°
18
76°
54°
19
79°
60°
20
86°
57°
21
81°
55°
22
77°
53°
23
72°
52°
24
71°
49°
25
69°
50°
26
70°
49°
27
71°
50°
28
73°
54°
29
75°
50°
30
77°
54°
1
Hist. Avg.
74°
52°
2
Hist. Avg.
73°
52°
3
Hist. Avg.
73°
52°
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 69° to 91°, with overnight lows between 49° and 69°. The average high for September is 79° with an average low of 57°. 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.
