S
M
T
W
T
F
S
30
79°
61°
31
81°
64°
1
84°
59°
2
85°
58°
3
78°
59°
4
79°
60°
5
80°
65°
6
84°
64°
7
86°
64°
8
80°
63°
9
78°
64°
10
83°
63°
11
83°
62°
12
81°
62°
13
80°
59°
14
80°
56°
15
76°
56°
16
75°
55°
17
75°
55°
18
76°
59°
19
78°
60°
20
79°
61°
21
80°
58°
22
78°
54°
23
75°
59°
24
74°
60°
25
79°
53°
26
74°
57°
27
77°
58°
28
78°
57°
29
Hist. Avg.
74°
53°
30
Hist. Avg.
74°
53°
1
Hist. Avg.
73°
52°
2
Hist. Avg.
73°
52°
3
Hist. Avg.
72°
52°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Cardiff
Cardiff's September 2026 forecast shows daily high temperatures ranging from 74° to 86°, with overnight lows between 53° and 65°. The average high for September is 79° with an average low of 60°. 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 Cardiff. See also: October | November | December.
