S
M
T
W
T
F
S
26
81°
50°
27
81°
62°
28
78°
64°
29
73°
50°
30
68°
48°
1
61°
45°
2
63°
39°
3
68°
40°
4
74°
48°
5
76°
56°
6
75°
50°
7
71°
51°
8
72°
50°
9
74°
53°
10
78°
52°
11
72°
54°
12
79°
57°
13
77°
56°
14
70°
51°
15
71°
50°
16
71°
49°
17
73°
50°
18
74°
52°
19
76°
54°
20
78°
56°
21
80°
57°
22
82°
58°
23
82°
59°
24
83°
60°
25
84°
61°
26
83°
60°
27
79°
56°
28
78°
61°
29
80°
61°
30
82°
60°
31
83°
61°
1
85°
62°
2
85°
63°
3
84°
63°
4
83°
62°
5
81°
63°
6
83°
62°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Belfast
Belfast's May 2026 forecast shows daily high temperatures ranging from 61° to 85°, with overnight lows between 39° and 64°. The average high for May is 77° with an average low of 55°. 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 Belfast. See also: June | July | August.