S
M
T
W
T
F
S
30
66°
54°
31
63°
55°
1
63°
55°
2
68°
57°
3
66°
57°
4
64°
54°
5
61°
52°
6
68°
57°
7
63°
52°
8
63°
50°
9
59°
50°
10
64°
54°
11
63°
54°
12
64°
54°
13
63°
54°
14
66°
57°
15
61°
55°
16
59°
54°
17
57°
52°
18
63°
52°
19
61°
52°
20
61°
50°
21
72°
55°
22
N/A
23
61°
48°
24
64°
52°
25
N/A
26
64°
55°
27
58°
44°
28
61°
51°
29
65°
56°
30
64°
49°
1
59°
47°
2
60°
50°
3
58°
47°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Londonderry
Londonderry's September 2026 forecast shows daily high temperatures ranging from 58° to 65°, with overnight lows between 44° and 56°. The average high for September is 61° with an average low of 50°. 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 Londonderry. See also: October | November | December.
