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September Weather in Charlestown, Ireland

Last updated: August 23, 2025

In Charlestown, Ireland, the average temperature in September hovers around 13°C (55°F), with a minimum dipping as low as 1°C (35°F) and a maximum reaching up to 24°C (76°F). Expect 90 mm (3.5 in) of precipitation spread across 18 days, contributing to a notably high average humidity of 88%. Stay prepared for a mix of pleasant and damp days!

September Temperature in Charlestown

In September in Charlestown, the average temperature is 13°C (55°F), with a maximum reaching 24°C (76°F) and a minimum dipping to as low as 1°C (35°F). This makes it an ideal time for travelers looking to enjoy mild weather while exploring the local attractions.

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

The chart illustrates September temperature patterns in Charlestown, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Charlestown, September typically has an average temperature of 13°C (55°F), with highs reaching up to 24°C (76°F) and lows dropping to around 1°C (35°F).
JanFebMarAprMayJunJulAugSepOctNovDec424344475256595855504643
Data source: Temperature data for Charlestown 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 Charlestown

In Charlestown in September, the total precipitation amount is 90 mm (3.5 in) distributed over 18 days.

September Precipitation Trends in Charlestown

The chart displays monthly precipitation patterns in Charlestown, 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 Charlestown, September typically receives around 90 mm (3.5 inches) of precipitation spread over approximately 18 days.
JanFebMarAprMayJunJulAugSepOctNovDec791241076582989614790120104109
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Charlestown

In Charlestown in September humidity is 88%. With an average temperature of 13°C (55°F), this humidity feels like a damp chill that clings to your skin, making it essential to dress in layers while exploring, as the moisture in the air can lead to a rather uncomfortable experience for traveling.

September Average Humidity in Charlestown

This chart illustrates the average monthly humidity levels in Charlestown, 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 Charlestown is approximately 88%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec89%88%87%86%83%83%85%85%88%91%92%89%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Charlestown

In Charlestown in September, the maximum UV index reaches 5, which corresponds to a moderate Exposure Category. Under these conditions, the estimated time to burn is approximately 30 minutes. For more details, you can check the Hourly UV Index in Charlestown.

Maximum UV Index Levels in Charlestown for September

The chart shows the monthly maximum UV Index (UVI) for Charlestown 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 Charlestown typically reaches 5, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec124578875321
Data source: Charlestown 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 Charlestown Compares to Other Months

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

This table compares monthly weather conditions in Charlestown, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather6°C (42°F)79 mm (3.1 inches)88%low
February Weather6°C (43°F)124 mm (4.9 inches)88%low
March Weather6°C (44°F)107 mm (4.2 inches)87%moderate
April Weather9°C (48°F)65 mm (2.6 inches)86%moderate
May Weather11°C (53°F)82 mm (3.2 inches)83%high
June Weather13°C (56°F)98 mm (3.8 inches)83%very high
July Weather15°C (59°F)96 mm (3.8 inches)85%very high
August Weather15°C (59°F)147 mm (5.8 inches)85%high
September Weather13°C (55°F)90 mm (3.5 inches)88%moderate
October Weather10°C (50°F)120 mm (4.7 inches)91%moderate
November Weather8°C (46°F)104 mm (4.1 inches)92%low
December Weather6°C (44°F)109 mm (4.3 inches)89%low

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