S
M
T
W
T
F
S
30
97°
64°
31
100°
64°
1
100°
68°
2
100°
72°
3
100°
72°
4
100°
72°
5
102°
73°
6
91°
75°
7
90°
66°
8
94°
73°
9
97°
72°
10
79°
62°
11
86°
65°
12
86°
66°
13
93°
71°
14
98°
70°
15
85°
61°
16
82°
58°
17
83°
60°
18
77°
57°
19
77°
53°
20
79°
56°
21
80°
55°
22
83°
60°
23
83°
60°
24
84°
59°
25
84°
61°
26
83°
61°
27
84°
60°
28
83°
61°
29
83°
60°
30
82°
59°
1
79°
54°
2
69°
48°
3
68°
46°
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 68° to 98°, with overnight lows between 46° and 73°. The average high for September is 83° with an average low of 60°. 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.
