S
M
T
W
T
F
S
30
90°
61°
31
90°
62°
1
89°
61°
2
88°
61°
3
88°
59°
4
85°
58°
5
84°
56°
6
81°
54°
7
84°
58°
8
87°
60°
9
88°
59°
10
86°
50°
11
78°
59°
12
84°
58°
13
85°
59°
14
86°
60°
15
87°
57°
16
85°
49°
17
74°
52°
18
83°
55°
19
75°
48°
20
83°
54°
21
83°
54°
22
Hist. Avg.
78°
46°
23
Hist. Avg.
78°
46°
24
Hist. Avg.
78°
45°
25
Hist. Avg.
77°
45°
26
Hist. Avg.
77°
45°
27
Hist. Avg.
76°
44°
28
Hist. Avg.
76°
44°
29
Hist. Avg.
75°
44°
30
Hist. Avg.
75°
43°
1
Hist. Avg.
74°
43°
2
Hist. Avg.
74°
43°
3
Hist. Avg.
73°
42°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Kennewick
Kennewick's September 2026 forecast shows daily high temperatures ranging from 74° to 90°, with overnight lows between 48° and 62°. The average high for September is 84° 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 Kennewick. See also: October | November | December.
