S
M
T
W
T
F
S
30
90°
75°
31
90°
75°
1
89°
74°
2
89°
74°
3
90°
73°
4
86°
74°
5
86°
74°
6
87°
72°
7
86°
70°
8
86°
71°
9
87°
74°
10
85°
74°
11
85°
73°
12
86°
74°
13
86°
74°
14
89°
70°
15
89°
72°
16
88°
72°
17
89°
71°
18
88°
70°
19
89°
69°
20
86°
69°
21
85°
70°
22
85°
68°
23
86°
68°
24
85°
69°
25
87°
69°
26
84°
70°
27
84°
68°
28
85°
68°
29
83°
69°
30
84°
69°
1
84°
68°
2
83°
68°
3
83°
67°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Umatilla
Umatilla's September 2026 forecast shows daily high temperatures ranging from 83° to 90°, with overnight lows between 67° and 75°. The average high for September is 86° with an average low of 71°. 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 Umatilla. See also: October | November | December.
