S
M
T
W
T
F
S
30
81°
47°
31
84°
45°
1
85°
46°
2
85°
45°
3
86°
48°
4
82°
45°
5
85°
50°
6
86°
50°
7
85°
49°
8
83°
50°
9
80°
49°
10
78°
48°
11
75°
48°
12
78°
47°
13
77°
49°
14
82°
47°
15
82°
48°
16
83°
47°
17
Hist. Avg.
78°
40°
18
Hist. Avg.
77°
40°
19
Hist. Avg.
77°
39°
20
Hist. Avg.
77°
39°
21
Hist. Avg.
76°
39°
22
Hist. Avg.
76°
38°
23
Hist. Avg.
75°
38°
24
Hist. Avg.
75°
37°
25
Hist. Avg.
75°
37°
26
Hist. Avg.
74°
37°
27
Hist. Avg.
74°
36°
28
Hist. Avg.
73°
36°
29
Hist. Avg.
73°
36°
30
Hist. Avg.
72°
35°
1
Hist. Avg.
72°
35°
2
Hist. Avg.
71°
35°
3
Hist. Avg.
71°
34°
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 75° to 86°, with overnight lows between 45° and 50°. The average high for September is 82° with an average low of 48°. 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.
