S
M
T
W
T
F
S
26
77°
59°
27
72°
52°
28
68°
50°
29
81°
59°
30
73°
63°
1
66°
55°
2
63°
52°
3
70°
45°
4
79°
45°
5
81°
52°
6
84°
61°
7
79°
63°
8
72°
52°
9
72°
59°
10
82°
59°
11
79°
57°
12
72°
52°
13
79°
45°
14
77°
55°
15
77°
43°
16
84°
52°
17
90°
66°
18
90°
63°
19
91°
63°
20
91°
66°
21
90°
66°
22
82°
68°
23
72°
68°
24
78°
69°
25
79°
69°
26
80°
69°
27
83°
68°
28
86°
67°
29
82°
67°
30
77°
63°
31
74°
58°
1
76°
62°
2
79°
61°
3
81°
63°
4
80°
65°
5
81°
65°
6
82°
64°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Union
Union's May 2026 forecast shows daily high temperatures ranging from 74° to 86°, with overnight lows between 58° and 69°. The average high for May is 80° with an average low of 65°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how May weather will actually feel in Union. See also: June | July | August.
