S
M
T
W
T
F
S
30
80°
48°
31
86°
45°
1
85°
55°
2
78°
58°
3
75°
54°
4
73°
51°
5
73°
51°
6
75°
55°
7
78°
57°
8
80°
55°
9
82°
57°
10
85°
60°
11
85°
60°
12
79°
56°
13
82°
59°
14
83°
60°
15
81°
53°
16
83°
57°
17
74°
53°
18
73°
50°
19
72°
48°
20
74°
58°
21
75°
54°
22
79°
57°
23
74°
50°
24
70°
47°
25
69°
45°
26
70°
49°
27
78°
53°
28
80°
55°
29
79°
54°
30
80°
55°
1
79°
54°
2
79°
54°
3
78°
53°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Kennewick
Kennewick's September 2026 forecast shows daily high temperatures ranging from 69° to 85°, with overnight lows between 45° and 60°. The average high for September is 77° with an average low of 54°. 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.
