S
M
T
W
T
F
S
30
71°
60°
31
69°
56°
1
69°
54°
2
71°
60°
3
72°
66°
4
66°
59°
5
66°
45°
6
75°
57°
7
66°
61°
8
64°
55°
9
64°
46°
10
64°
52°
11
66°
50°
12
64°
61°
13
66°
64°
14
66°
64°
15
66°
55°
16
61°
55°
17
64°
57°
18
64°
57°
19
N/A
20
66°
49°
21
69°
54°
22
69°
56°
23
63°
43°
24
65°
52°
25
66°
51°
26
64°
56°
27
65°
53°
28
63°
52°
29
64°
57°
30
65°
54°
1
62°
52°
2
63°
50°
3
58°
50°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Carmarthen
Carmarthen's September 2026 forecast shows daily high temperatures ranging from 58° to 69°, with overnight lows between 43° and 57°. The average high for September is 64° 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 Carmarthen. See also: October | November | December.
