S
M
T
W
T
F
S
30
79°
48°
31
88°
45°
1
86°
56°
2
77°
56°
3
68°
48°
4
76°
42°
5
74°
51°
6
71°
53°
7
78°
54°
8
81°
44°
9
86°
44°
10
90°
46°
11
77°
48°
12
75°
56°
13
63°
53°
14
74°
47°
15
75°
46°
16
79°
46°
17
82°
50°
18
84°
53°
19
83°
54°
20
82°
51°
21
81°
50°
22
82°
49°
23
79°
50°
24
78°
46°
25
70°
50°
26
71°
49°
27
71°
44°
28
68°
42°
29
69°
42°
30
68°
39°
1
72°
49°
2
73°
47°
3
77°
47°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Hermiston
Hermiston's September 2026 forecast shows daily high temperatures ranging from 63° to 84°, with overnight lows between 39° and 56°. The average high for September is 75° with an average low of 48°. 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 Hermiston. See also: October | November | December.
