S
M
T
W
T
F
S
30
79°
50°
31
78°
51°
1
79°
50°
2
77°
49°
3
77°
52°
4
78°
50°
5
77°
55°
6
83°
51°
7
83°
54°
8
84°
56°
9
83°
57°
10
79°
54°
11
84°
45°
12
75°
44°
13
73°
48°
14
74°
44°
15
73°
44°
16
72°
45°
17
71°
43°
18
74°
53°
19
78°
45°
20
75°
43°
21
74°
41°
22
68°
40°
23
78°
52°
24
79°
50°
25
Hist. Avg.
74°
44°
26
Hist. Avg.
74°
44°
27
Hist. Avg.
73°
43°
28
Hist. Avg.
72°
43°
29
Hist. Avg.
72°
42°
30
Hist. Avg.
71°
42°
1
Hist. Avg.
71°
42°
2
Hist. Avg.
70°
41°
3
Hist. Avg.
70°
41°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Belfast
Belfast's September 2026 forecast shows daily high temperatures ranging from 68° to 84°, with overnight lows between 40° and 57°. The average high for September is 77° with an average low of 49°. 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 Belfast. See also: October | November | December.
