S
M
T
W
T
F
S
30
90°
76°
31
90°
75°
1
89°
76°
2
90°
75°
3
89°
75°
4
87°
73°
5
90°
74°
6
89°
75°
7
90°
74°
8
89°
73°
9
88°
74°
10
90°
75°
11
89°
74°
12
88°
74°
13
89°
73°
14
87°
74°
15
86°
74°
16
85°
73°
17
85°
72°
18
86°
72°
19
86°
73°
20
85°
68°
21
84°
68°
22
85°
71°
23
87°
72°
24
86°
70°
25
87°
71°
26
86°
72°
27
87°
71°
28
86°
70°
29
83°
69°
30
86°
69°
1
Hist. Avg.
85°
66°
2
Hist. Avg.
85°
66°
3
Hist. Avg.
85°
65°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Sunnyside
Sunnyside's September 2026 forecast shows daily high temperatures ranging from 83° to 90°, with overnight lows between 68° and 76°. The average high for September is 87° with an average low of 73°. 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 Sunnyside. See also: October | November | December.
