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September Weather in Merthyr Tydfil, United Kingdom

Last updated: August 27, 2025

In September, the average temperature in Merthyr Tydfil, United Kingdom hovers around 13°C (56°F). Expect a minimum of 2°C (36°F) and a maximum reaching 27°C (81°F). Be prepared for approximately 92 mm (3.6 in) of precipitation spread over 13 days, with an average humidity level of 79%.

September Temperature in Merthyr Tydfil

In September in Merthyr Tydfil, the average temperature is a comfortable 13°C (56°F), with maximums potentially reaching 27°C (81°F) and minimums dropping as low as 2°C (36°F). This makes it an ideal time for travelers looking to enjoy mild weather and outdoor activities.

September Weather in Merthyr Tydfil: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Merthyr Tydfil, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Merthyr Tydfil, September typically has an average temperature of 13°C (56°F), with highs reaching up to 27°C (81°F) and lows dropping to around 2°C (36°F).
JanFebMarAprMayJunJulAugSepOctNovDec404143475258615956514543
Data source: Temperature data for Merthyr Tydfil generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Merthyr Tydfil

In Merthyr Tydfil in September, the precipitation amount is 92 mm (3.6 in) spread over 13 days.

September Precipitation Trends in Merthyr Tydfil

The chart displays monthly precipitation patterns in Merthyr Tydfil, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Merthyr Tydfil, September typically receives around 92 mm (3.6 inches) of precipitation spread over approximately 13 days.
JanFebMarAprMayJunJulAugSepOctNovDec821241116493919311492143117144
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Merthyr Tydfil

In Merthyr Tydfil in September, humidity is 79%. With an average temperature of 13°C (56°F), this humidity feels like a damp, cool blanket wrapping around you, making traveling slightly uncomfortable and requiring you to dress in layers to stay comfortable while exploring.

September Average Humidity in Merthyr Tydfil

This chart illustrates the average monthly humidity levels in Merthyr Tydfil, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Merthyr Tydfil is approximately 79%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec89%88%86%84%80%80%70%73%79%89%90%89%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Merthyr Tydfil

In Merthyr Tydfil in September, the maximum UV index is 6, which corresponds to a high Exposure Category. The time to burn is approximately 25 minutes. To find the hourly UV index in Merthyr Tydfil, you can refer to this Hourly UV Index in Merthyr Tydfil.

Maximum UV Index Levels in Merthyr Tydfil for September

The chart shows the monthly maximum UV Index (UVI) for Merthyr Tydfil in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in Merthyr Tydfil typically reaches 6, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec124678876421
Data source: Merthyr Tydfil September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

How September Weather in Merthyr Tydfil Compares to Other Months

Weather in Merthyr Tydfil varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Merthyr Tydfil, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Merthyr Tydfil, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather4°C (40°F)82 mm (3.2 inches)88%low
February Weather5°C (42°F)124 mm (4.9 inches)88%low
March Weather6°C (43°F)111 mm (4.4 inches)86%moderate
April Weather8°C (47°F)64 mm (2.5 inches)84%high
May Weather11°C (52°F)93 mm (3.7 inches)80%high
June Weather14°C (58°F)91 mm (3.6 inches)80%very high
July Weather16°C (61°F)93 mm (3.7 inches)70%very high
August Weather15°C (60°F)114 mm (4.5 inches)73%high
September Weather13°C (56°F)92 mm (3.6 inches)79%high
October Weather10°C (51°F)143 mm (5.6 inches)89%moderate
November Weather7°C (45°F)117 mm (4.6 inches)90%low
December Weather6°C (43°F)144 mm (5.7 inches)89%low

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