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September Weather in St Helens, United Kingdom

Last updated: August 27, 2025

In September, the average temperature in St Helens, United Kingdom hovers around 14°C (58°F). Be prepared for a range of temperatures, with a minimum of 4°C (39°F) and a maximum soaring up to 28°C (82°F). Expect 99 mm (3.9 in) of precipitation spread over about 13 days, contributing to a high average humidity of 85%.

September Temperature in St Helens

In September in St Helens, the average temperature is 14°C (58°F). The maximum can reach 28°C (82°F) and the minimum can be as low as 4°C (39°F). It's a great time to visit, as you can enjoy mild days and cool nights perfect for exploring.

September Weather in St Helens: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in St Helens, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In St Helens, September typically has an average temperature of 14°C (58°F), with highs reaching up to 28°C (82°F) and lows dropping to around 4°C (39°F).
JanFebMarAprMayJunJulAugSepOctNovDec424345485460626158534743
Data source: Temperature data for St Helens 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 St Helens

In St Helens in September, the precipitation amount is 99 mm (3.9 in) over the course of 13 days.

September Precipitation Trends in St Helens

The chart displays monthly precipitation patterns in St Helens, 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 St Helens, September typically receives around 99 mm (3.9 inches) of precipitation spread over approximately 13 days.
JanFebMarAprMayJunJulAugSepOctNovDec758897506297981199911897115
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in St Helens

In St Helens in September, humidity is 85%. With an average temperature of 14°C (58°F), this humidity feels like a thick blanket wrapping around you, making even short walks feel heavy and exhausting for traveling.

September Average Humidity in St Helens

This chart illustrates the average monthly humidity levels in St Helens, 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 St Helens is approximately 85%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec89%88%86%85%79%81%78%79%85%90%91%89%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in St Helens

In St Helens 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 St Helens.

Maximum UV Index Levels in St Helens for September

The chart shows the monthly maximum UV Index (UVI) for St Helens 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 St Helens typically reaches 5, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec123578875421
Data source: St Helens 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 St Helens Compares to Other Months

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

This table compares monthly weather conditions in St Helens, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather6°C (42°F)75 mm (3.0 inches)89%low
February Weather6°C (43°F)88 mm (3.5 inches)88%low
March Weather7°C (45°F)97 mm (3.8 inches)86%moderate
April Weather9°C (49°F)50 mm (2.0 inches)84%moderate
May Weather12°C (54°F)62 mm (2.4 inches)79%high
June Weather15°C (60°F)97 mm (3.8 inches)81%very high
July Weather17°C (63°F)98 mm (3.9 inches)78%very high
August Weather16°C (62°F)119 mm (4.7 inches)79%high
September Weather14°C (58°F)99 mm (3.9 inches)85%moderate
October Weather11°C (53°F)117 mm (4.6 inches)90%moderate
November Weather8°C (47°F)97 mm (3.8 inches)91%low
December Weather6°C (44°F)115 mm (4.5 inches)89%low

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