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September Weather in Seinaejoki, Finland

Last updated: August 23, 2025

In Seinaejoki, Finland, the average temperature for September hovers around 10°C (50°F). Expect a range where the minimum dips to -4°C (26°F) and the maximum peaks at 24°C (75°F). With precipitation totaling 71 mm (2.8 in) over 13 days, it’s a month with consistent moisture. The air feels quite damp, with an average humidity level of 89%.

September Temperature in Seinaejoki

In September in Seinaejoki, the average temperature is 10°C (50°F), with a maximum that can reach 24°C (75°F) and a minimum that can drop as low as -4°C (26°F). Be prepared for a wide range of temperatures when traveling to Seinaejoki this month.

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

The chart illustrates September temperature patterns in Seinaejoki, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Seinaejoki, September typically has an average temperature of 10°C (50°F), with highs reaching up to 24°C (75°F) and lows dropping to around -4°C (26°F).
JanFebMarAprMayJunJulAugSepOctNovDec242229384860625950413427
Data source: Temperature data for Seinaejoki 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 Seinaejoki

In Seinaejoki in September, the total precipitation amount is 71 mm (2.8 in) occurring over the course of 13 days.

September Precipitation Trends in Seinaejoki

The chart displays monthly precipitation patterns in Seinaejoki, 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 Seinaejoki, September typically receives around 71 mm (2.8 inches) of precipitation spread over approximately 13 days.
JanFebMarAprMayJunJulAugSepOctNovDec373941446061599071755847
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Seinaejoki

In Seinaejoki in September, humidity is 89%. With an average temperature of 10°C (50°F), this humidity feels like a dense blanket wrapping around you, making travel feel damp and chilly, and urging you to dress in layers for comfort.

September Average Humidity in Seinaejoki

This chart illustrates the average monthly humidity levels in Seinaejoki, 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 Seinaejoki is approximately 89%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec97%95%92%85%77%74%79%82%89%93%93%95%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Seinaejoki

In Seinaejoki in September, the maximum UV index is 3, which corresponds to a moderate Exposure Category. The time to burn is approximately 30 minutes. For more details on the hourly UV index in Seinaejoki, you can check the information here.

Maximum UV Index Levels in Seinaejoki for September

The chart shows the monthly maximum UV Index (UVI) for Seinaejoki 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 Seinaejoki typically reaches 3, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec113456653211
Data source: Seinaejoki 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 Seinaejoki Compares to Other Months

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

This table compares monthly weather conditions in Seinaejoki, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-4°C (24°F)37 mm (1.4 inches)97%low
February Weather-5°C (22°F)39 mm (1.5 inches)95%low
March Weather-2°C (29°F)41 mm (1.6 inches)92%moderate
April Weather3°C (38°F)44 mm (1.7 inches)85%moderate
May Weather9°C (49°F)60 mm (2.3 inches)77%moderate
June Weather15°C (60°F)61 mm (2.4 inches)74%high
July Weather17°C (63°F)59 mm (2.3 inches)79%high
August Weather15°C (59°F)90 mm (3.6 inches)82%moderate
September Weather10°C (50°F)71 mm (2.8 inches)89%moderate
October Weather5°C (41°F)75 mm (2.9 inches)93%low
November Weather1°C (34°F)58 mm (2.3 inches)93%low
December Weather-3°C (28°F)47 mm (1.9 inches)95%low

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