S
M
T
W
T
F
S
30
94°
71°
31
96°
71°
1
99°
72°
2
99°
72°
3
100°
73°
4
99°
75°
5
93°
72°
6
102°
72°
7
101°
70°
8
91°
69°
9
94°
69°
10
90°
71°
11
90°
69°
12
90°
70°
13
89°
69°
14
87°
68°
15
88°
67°
16
87°
66°
17
85°
63°
18
86°
62°
19
84°
60°
20
82°
61°
21
86°
60°
22
89°
65°
23
88°
64°
24
88°
65°
25
87°
65°
26
88°
64°
27
88°
64°
28
87°
63°
29
86°
64°
30
87°
64°
1
86°
60°
2
84°
56°
3
76°
52°
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 76° to 94°, with overnight lows between 52° and 71°. The average high for September is 87° with an average low of 64°. 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.
