Treharris (Merthyr Tydfil) weather

Forecast days

Heavy rain.
Sunrise iconSunrise:
Sunset iconSunset:
M UV
L Pollution
No pollen data.

7 day forecast for Treharris

Today (16 September 2025)
Time
23:00
Weather symbols Heavy rain
Chance of precipitation
≥95%
Temperature
12°
Feels like temperature (°C)
12°
Wind direction and speed
SSW
5
Wind gust (mph)
15
Visibility
M
Humidity
96%
UV -
Wednesday (17 September 2025)
Time
00:00
01:00
02:00
03:00
04:00
05:00
06:00
07:00
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
20:00
21:00
22:00
23:00
Weather symbols Heavy rain Heavy rain Heavy rain Heavy rain Heavy rain Heavy rain Heavy rain Heavy rain Heavy rain Heavy rain Heavy rain Heavy rain Heavy rain Heavy rain Heavy rain Heavy rain Light rain Light rain Heavy rain Light rain Light rain Light rain Light rain Light rain
Chance of precipitation
≥95%
≥95%
≥95%
≥95%
≥95%
≥95%
≥95%
≥95%
≥95%
≥95%
≥95%
≥95%
≥95%
90%
90%
90%
90%
80%
80%
80%
80%
80%
90%
90%
Temperature (°C)
12°
12°
12°
13°
13°
13°
13°
14°
14°
15°
16°
16°
16°
17°
17°
17°
17°
17°
17°
16°
16°
16°
16°
16°
Feels like temperature (°C)
11°
11°
11°
11°
11°
11°
11°
12°
12°
13°
13°
14°
14°
14°
15°
15°
15°
15°
15°
15°
15°
15°
15°
15°
Wind direction and speed (mph)
SSW
6
S
7
S
8
S
9
S
9
S
9
S
10
SSW
11
SW
13
SW
15
SW
16
SW
16
WSW
16
WSW
16
WSW
15
WSW
15
WSW
14
WSW
13
WSW
13
WSW
12
WSW
12
WSW
11
SW
11
SW
11
Wind gust (mph)
19
21
23
25
26
27
30
34
35
36
36
35
35
33
33
32
31
29
27
25
24
24
24
24
Visibility (description)
P
M
M
M
P
P
P
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
Humidity
97%
97%
98%
98%
97%
97%
98%
98%
98%
98%
98%
98%
97%
97%
98%
98%
97%
98%
98%
98%
98%
98%
99%
99%
UV - - - - - - 1 1 1 1 1 1 1 1 2 2 1 1 1 1 - - - -
Thursday (18 September 2025)
Time
00:00
01:00
02:00
03:00
04:00
05:00
06:00
07:00
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
20:00
21:00
22:00
23:00
Weather symbols Light rain Light rain Light rain Light rain Light rain Light rain Light rain Light rain Overcast Overcast Overcast Overcast Overcast Overcast Overcast Overcast Overcast Overcast Overcast Overcast Overcast Overcast Overcast Overcast
Chance of precipitation
90%
80%
80%
80%
80%
80%
70%
60%
50%
40%
30%
20%
10%
10%
10%
10%
10%
10%
10%
10%
20%
10%
10%
10%
Temperature (°C)
16°
16°
16°
16°
16°
16°
16°
16°
16°
16°
17°
17°
18°
19°
19°
19°
19°
19°
18°
18°
17°
17°
16°
16°
Feels like temperature (°C)
15°
15°
15°
15°
15°
15°
14°
14°
14°
14°
15°
15°
16°
16°
17°
17°
17°
17°
17°
17°
16°
16°
15°
15°
Wind direction and speed (mph)
SW
11
SW
11
SW
12
SW
12
SW
13
SW
14
SW
14
SW
13
SW
13
SW
13
SW
13
SW
13
SW
14
SW
15
SW
14
SW
14
SW
13
SW
12
SW
11
SW
10
SW
9
SSW
8
SSW
8
SSW
8
Wind gust (mph)
24
26
26
29
30
30
30
30
29
30
31
32
32
33
32
32
30
28
26
25
24
24
23
21
Visibility (description)
M
M
M
M
M
M
M
M
G
VG
VG
VG
VG
VG
VG
VG
VG
VG
VG
VG
VG
VG
VG
VG
Humidity
98%
98%
99%
98%
98%
98%
97%
96%
95%
93%
93%
88%
87%
83%
82%
80%
81%
83%
85%
86%
88%
90%
91%
91%
UV - - - - - - 1 1 1 1 1 2 2 3 2 2 1 1 1 1 - - - -
Friday (19 September 2025)
Time
00:00
01:00
02:00
03:00
04:00
05:00
06:00
07:00
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
20:00
21:00
22:00
23:00
Weather symbols Overcast Overcast Overcast Overcast Overcast Overcast Overcast Overcast Overcast Overcast Overcast Overcast Overcast Cloudy Cloudy Overcast Cloudy Cloudy Cloudy Cloudy Cloudy Cloudy Cloudy Light rain
Chance of precipitation
10%
10%
10%
10%
10%
20%
20%
20%
30%
30%
30%
30%
40%
30%
30%
30%
30%
30%
40%
40%
40%
40%
50%
50%
Temperature (°C)
16°
16°
15°
15°
15°
15°
15°
14°
15°
15°
16°
16°
17°
18°
18°
18°
18°
18°
17°
17°
16°
15°
15°
15°
Feels like temperature (°C)
15°
15°
15°
15°
14°
14°
14°
14°
14°
14°
15°
16°
16°
17°
17°
17°
17°
17°
17°
16°
16°
16°
15°
15°
Wind direction and speed (mph)
SSW
7
SSW
6
SSW
6
SSW
6
S
6
SSW
5
S
5
S
5
S
5
S
6
SSW
7
SSW
7
SSW
8
SSW
8
SSW
9
SW
9
SW
8
SW
8
SW
7
SW
6
SW
5
SW
4
WSW
3
WSW
3
Wind gust (mph)
18
16
15
15
14
13
12
11
14
17
19
18
19
19
19
18
15
13
12
12
9
7
6
6
Visibility (description)
VG
VG
VG
VG
VG
VG
VG
VG
VG
VG
VG
VG
VG
VG
VG
VG
VG
VG
VG
VG
VG
VG
VG
G
Humidity
91%
92%
92%
93%
94%
94%
95%
95%
94%
92%
91%
87%
86%
85%
82%
84%
85%
88%
90%
92%
94%
94%
95%
95%
UV - - - - - - 1 1 1 1 1 2 3 2 2 2 1 1 1 1 - - - -
Saturday (20 September 2025)
Time
00:00
01:00
02:00
03:00
04:00
05:00
06:00
07:00
08:00
09:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
17:00
18:00
19:00
20:00
21:00
22:00
23:00
Weather symbols Cloudy Cloudy Cloudy Cloudy Light rain Light rain Light rain Cloudy Cloudy Cloudy Cloudy Cloudy Light shower day Light shower day Light shower day Light shower day Sunny intervals Sunny intervals Sunny intervals Partly cloudy night Partly cloudy night Partly cloudy night Partly cloudy night Partly cloudy night
Chance of precipitation
50%
50%
40%
50%
60%
60%
50%
50%
50%
40%
40%
40%
50%
60%
60%
50%
40%
50%
40%
40%
40%
40%
30%
30%
Temperature (°C)
14°
14°
14°
14°
13°
13°
13°
13°
13°
13°
14°
14°
15°
15°
15°
15°
15°
15°
14°
13°
12°
12°
12°
11°
Feels like temperature (°C)
15°
14°
14°
14°
14°
13°
13°
12°
12°
12°
13°
13°
13°
14°
13°
13°
13°
13°
13°
12°
11°
11°
10°
10°
Wind direction and speed (mph)
W
3
WSW
3
WSW
3
WSW
3
WSW
3
WSW
4
W
4
W
4
WNW
4
WNW
5
WSW
6
WSW
7
W
8
W
9
W
10
W
10
W
10
W
9
WNW
9
WNW
8
NW
7
NW
7
NW
8
NNW
8
Wind gust (mph)
6
6
6
6
7
8
8
9
12
14
13
16
17
18
19
19
18
17
16
16
16
16
16
15
Visibility (description)
G
VG
G
G
G
G
G
G
VG
VG
VG
E
E
E
E
E
E
E
E
E
E
E
E
E
Humidity
95%
95%
95%
96%
95%
95%
95%
95%
94%
92%
90%
88%
85%
82%
76%
73%
74%
72%
76%
80%
85%
86%
87%
87%
UV - - - - - - 1 1 1 1 1 2 2 2 3 2 2 1 1 1 - - - -
Sunday (21 September 2025)
Time
00:00
01:00
04:00
07:00
10:00
13:00
16:00
19:00
22:00
Weather symbols Partly cloudy night Partly cloudy night Cloudy Sunny intervals Cloudy Cloudy Cloudy Cloudy Cloudy
Chance of precipitation
30%
40%
40%
40%
40%
30%
20%
20%
10%
Temperature (°C)
11°
11°
10°
11°
12°
13°
11°
Feels like temperature (°C)
10°
10°
Wind direction and speed (mph)
NNW
8
NNW
8
NNW
9
N
9
N
12
NNE
13
NNE
13
NNE
11
N
9
Wind gust (mph)
15
13
14
21
26
26
25
18
15
Visibility (description)
E
E
VG
VG
VG
VG
VG
VG
VG
Humidity
89%
89%
88%
88%
78%
71%
63%
68%
73%
UV - - - 1 2 3 1 1 -
Monday (22 September 2025)
Time
01:00
04:00
07:00
10:00
13:00
16:00
19:00
22:00
Weather symbols Cloudy Partly cloudy night Sunny intervals Sunny intervals Cloudy Sunny intervals Partly cloudy night Partly cloudy night
Chance of precipitation
10%
10%
10%
10%
10%
10%
10%
<5%
Temperature (°C)
11°
13°
14°
11°
Feels like temperature (°C)
11°
11°
10°
Wind direction and speed (mph)
NNE
8
NNE
8
NNE
7
NNE
10
NE
12
NE
11
NE
9
NNE
8
Wind gust (mph)
12
12
15
20
21
19
12
10
Visibility (description)
VG
VG
VG
VG
VG
VG
VG
VG
Humidity
75%
78%
80%
68%
56%
54%
62%
71%
UV - - 1 2 4 2 1 -

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WARNING
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Flood alerts in force for Wales
Flood alerts in force for Wales

Wales weather forecast

Headline:

Remaining changeable with rain tonight.

This Evening and Tonight:

Cloudy this evening then turning increasingly wet and windy overnight with a band of heavy and persistent rain pushing eastwards. Rain most persistent over the mountains, with flooding possible. Mild overnight. Minimum temperature 11 °C.

Wednesday:

Heavy, persistent rain clearing eastwards through the morning, though remaining cloudy with outbreaks of patchy rain and drizzle throughout the day, turning heavy at times over the hills. Breezy. Maximum temperature 18 °C.

Outlook for Thursday to Saturday:

Remaining changeable with showers or longer spells of rain at times, though brighter interludes are possible. Often breezy. A little milder and more humid by the end of the week.

Updated:

UK long range weather forecast

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