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September Weather in Karstula, Finland

Last updated: August 23, 2025

In September, the average temperature in Karstula, Finland hovers around 9°C (49°F). Expect a range from a chilly -5°C (23°F) to a warm 22°C (73°F). With 74 mm (2.9 in) of precipitation spread over 13 days, it's advisable to carry an umbrella. Additionally, the air tends to feel quite damp, with an average humidity of 89%.

September Temperature in Karstula

In September in Karstula, the average temperature is 9°C (49°F), with maximums reaching 22°C (73°F) and minimums dropping as low as -5°C (23°F). This variation in temperature makes Karstula an interesting destination for travelers seeking both mild days and crisp evenings.

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

The chart illustrates September temperature patterns in Karstula, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Karstula, September typically has an average temperature of 9°C (49°F), with highs reaching up to 22°C (73°F) and lows dropping to around -5°C (23°F).
JanFebMarAprMayJunJulAugSepOctNovDec222027354759615848393225
Data source: Temperature data for Karstula 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 Karstula

In Karstula in September, the precipitation amount is 74 mm (2.9 in) over the course of 13 days.

September Precipitation Trends in Karstula

The chart displays monthly precipitation patterns in Karstula, 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 Karstula, September typically receives around 74 mm (2.9 inches) of precipitation spread over approximately 13 days.
JanFebMarAprMayJunJulAugSepOctNovDec444341466461669074766459
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Karstula

In Karstula in September, humidity is 89%. With an average temperature of 9°C (49°F), this humidity feels like a persistent dampness that clings to your clothes and skin, making it challenging to stay comfortable while traveling.

September Average Humidity in Karstula

This chart illustrates the average monthly humidity levels in Karstula, 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 Karstula 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 Karstula

In Karstula 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 Karstula, you can check the information here.

Maximum UV Index Levels in Karstula for September

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

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

This table compares monthly weather conditions in Karstula, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-6°C (22°F)44 mm (1.7 inches)97%low
February Weather-7°C (20°F)43 mm (1.7 inches)95%low
March Weather-3°C (27°F)41 mm (1.6 inches)92%moderate
April Weather2°C (35°F)46 mm (1.8 inches)85%moderate
May Weather8°C (47°F)64 mm (2.5 inches)77%moderate
June Weather15°C (60°F)61 mm (2.4 inches)74%high
July Weather16°C (62°F)66 mm (2.6 inches)79%high
August Weather14°C (58°F)90 mm (3.6 inches)82%moderate
September Weather9°C (49°F)74 mm (2.9 inches)89%moderate
October Weather4°C (40°F)76 mm (3.0 inches)93%low
November Weather0°C (33°F)64 mm (2.5 inches)93%low
December Weather-4°C (26°F)59 mm (2.3 inches)95%low

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