S
M
T
W
T
F
S
30
82°
55°
31
82°
56°
1
68°
61°
2
73°
63°
3
78°
60°
4
83°
58°
5
73°
55°
6
74°
50°
7
78°
53°
8
78°
51°
9
75°
59°
10
77°
53°
11
70°
52°
12
70°
54°
13
72°
53°
14
76°
56°
15
79°
56°
16
78°
51°
17
75°
55°
18
67°
49°
19
74°
54°
20
72°
53°
21
70°
52°
22
71°
53°
23
70°
53°
24
71°
52°
25
67°
52°
26
71°
51°
27
71°
53°
28
70°
50°
29
63°
48°
30
65°
48°
1
63°
46°
2
61°
47°
3
62°
48°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Londonderry
Londonderry's September 2026 forecast shows daily high temperatures ranging from 61° to 83°, with overnight lows between 46° and 60°. The average high for September is 72° with an average low of 52°. 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.
