S
M
T
W
T
F
S
30
91°
63°
31
90°
66°
1
96°
71°
2
93°
70°
3
95°
70°
4
93°
68°
5
86°
68°
6
79°
55°
7
82°
54°
8
86°
59°
9
90°
68°
10
81°
68°
11
81°
63°
12
81°
64°
13
88°
63°
14
73°
52°
15
86°
50°
16
90°
68°
17
91°
70°
18
77°
63°
19
86°
61°
20
82°
66°
21
68°
55°
22
63°
55°
23
66°
59°
24
68°
46°
25
72°
41°
26
73°
43°
27
73°
43°
28
75°
45°
29
77°
45°
30
79°
54°
1
86°
59°
2
73°
57°
3
70°
46°
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 ° to °, with overnight lows between ° and °. The average high for September is ° with an average low of °. 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.
