S
M
T
W
T
F
S
30
79°
59°
31
76°
60°
1
82°
60°
2
83°
55°
3
82°
50°
4
74°
53°
5
74°
59°
6
81°
53°
7
78°
50°
8
73°
51°
9
72°
55°
10
73°
57°
11
74°
58°
12
80°
57°
13
80°
56°
14
79°
49°
15
73°
48°
16
69°
52°
17
70°
47°
18
70°
46°
19
71°
44°
20
68°
44°
21
67°
47°
22
68°
52°
23
71°
45°
24
72°
52°
25
74°
53°
26
71°
52°
27
75°
53°
28
75°
48°
29
74°
47°
30
64°
47°
1
68°
48°
2
73°
49°
3
65°
40°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Darien
Darien's September 2026 forecast shows daily high temperatures ranging from 64° to 83°, with overnight lows between 40° and 60°. The average high for September is 74° with an average low of 51°. 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 Darien. See also: October | November | December.
