S
M
T
W
T
F
S
30
99°
66°
31
99°
70°
1
99°
72°
2
97°
74°
3
94°
71°
4
98°
72°
5
96°
72°
6
99°
74°
7
100°
74°
8
99°
74°
9
98°
75°
10
97°
73°
11
89°
68°
12
88°
64°
13
88°
66°
14
86°
63°
15
88°
68°
16
90°
67°
17
90°
68°
18
89°
68°
19
90°
67°
20
89°
67°
21
88°
66°
22
88°
66°
23
87°
65°
24
88°
65°
25
88°
64°
26
87°
65°
27
88°
64°
28
88°
64°
29
87°
63°
30
88°
64°
1
87°
63°
2
86°
63°
3
86°
62°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Union
Union's September 2026 forecast shows daily high temperatures ranging from 86° to 100°, with overnight lows between 62° and 75°. The average high for September is 91° with an average low of 68°. 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 Union. See also: October | November | December.
