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September Weather in Mullion, United Kingdom

Last updated: August 27, 2025

In Mullion, United Kingdom, the average temperature in September is a comfortable 16°C (60°F), with a low of 10°C (50°F) and a high reaching 22°C (72°F). Be prepared for some rainfall, as the area experiences an average precipitation of 64 mm (2.5 in) over 12 days. Additionally, expect a sense of humidity with an average of 84% throughout the month.

September Temperature in Mullion

In September in Mullion, the average temperature is 16°C (60°F). Maximums can reach 22°C (72°F), while minimums can be as low as 10°C (50°F). This mild climate makes Mullion an ideal destination for travelers looking to explore comfortably.

September Weather in Mullion: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Mullion, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Mullion, September typically has an average temperature of 16°C (60°F), with highs reaching up to 22°C (72°F) and lows dropping to around 10°C (50°F).
JanFebMarAprMayJunJulAugSepOctNovDec474848505459636260565250
Data source: Temperature data for Mullion 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 Mullion

In Mullion in September, the total precipitation amount is 64 mm (2.5 in) over the course of 12 days.

September Precipitation Trends in Mullion

The chart displays monthly precipitation patterns in Mullion, 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 Mullion, September typically receives around 64 mm (2.5 inches) of precipitation spread over approximately 12 days.
JanFebMarAprMayJunJulAugSepOctNovDec739085466474705764120102123
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Mullion

In Mullion in September humidity is 84%. With an average temperature of 16°C (60°F), this humidity feels like a warm, heavy blanket wrapping around you, making outdoor activities feel muggy and potentially exhausting for travelers.

September Average Humidity in Mullion

This chart illustrates the average monthly humidity levels in Mullion, 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 Mullion is approximately 84%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec81%84%82%83%85%85%85%85%84%84%82%81%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Mullion

In Mullion 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 Mullion, you can refer to this Hourly UV Index in Mullion.

Maximum UV Index Levels in Mullion for September

The chart shows the monthly maximum UV Index (UVI) for Mullion 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 Mullion typically reaches 6, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec234679886421
Data source: Mullion 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 Mullion Compares to Other Months

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

This table compares monthly weather conditions in Mullion, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather8°C (47°F)73 mm (2.9 inches)81%low
February Weather9°C (48°F)90 mm (3.5 inches)83%moderate
March Weather9°C (48°F)85 mm (3.4 inches)82%moderate
April Weather10°C (50°F)45 mm (1.8 inches)83%high
May Weather12°C (54°F)64 mm (2.5 inches)85%high
June Weather15°C (59°F)74 mm (2.9 inches)85%very high
July Weather17°C (63°F)70 mm (2.8 inches)85%very high
August Weather17°C (62°F)57 mm (2.3 inches)85%very high
September Weather16°C (60°F)64 mm (2.5 inches)84%high
October Weather13°C (56°F)120 mm (4.7 inches)84%moderate
November Weather11°C (52°F)102 mm (4.0 inches)82%low
December Weather10°C (50°F)123 mm (4.8 inches)81%low

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