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September Weather in Janakkala, Finland

Last updated: August 23, 2025

In September, the average temperature in Janakkala, Finland hovers around 11°C (52°F). Be prepared for a temperature range that can dip as low as -2°C (29°F) and rise to a pleasant 23°C (74°F). Expect about 65 mm (2.6 in) of precipitation spread over 13 days, accompanied by an average humidity level of 90%, creating a crisp and sometimes damp atmosphere.

September Temperature in Janakkala

In September in Janakkala, the average temperature is 11°C (52°F). The maximum can reach 23°C (74°F) and the minimum can be as low as -2°C (29°F). Be sure to pack layers to stay comfortable during your travels!

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

The chart illustrates September temperature patterns in Janakkala, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Janakkala, September typically has an average temperature of 11°C (52°F), with highs reaching up to 23°C (74°F) and lows dropping to around -2°C (29°F).
JanFebMarAprMayJunJulAugSepOctNovDec252429385061636052433628
Data source: Temperature data for Janakkala 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 Janakkala

In Janakkala in September, the precipitation amount is 65 mm (2.6 in) spread over a duration of 13 days.

September Precipitation Trends in Janakkala

The chart displays monthly precipitation patterns in Janakkala, 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 Janakkala, September typically receives around 65 mm (2.6 inches) of precipitation spread over approximately 13 days.
JanFebMarAprMayJunJulAugSepOctNovDec484143466071858065755263
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Janakkala

In Janakkala in September, humidity is 90%. With an average temperature of 11°C (52°F), this humidity feels like a heavy blanket that clings to your skin, making travel uncomfortable and muggy.

September Average Humidity in Janakkala

This chart illustrates the average monthly humidity levels in Janakkala, 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 Janakkala is approximately 90%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec97%95%93%87%75%75%80%83%90%93%94%95%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Janakkala

In Janakkala 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 Janakkala, you can check the information here.

Maximum UV Index Levels in Janakkala for September

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

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

This table compares monthly weather conditions in Janakkala, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-4°C (25°F)48 mm (1.9 inches)97%low
February Weather-5°C (24°F)41 mm (1.6 inches)95%low
March Weather-2°C (29°F)43 mm (1.7 inches)93%moderate
April Weather3°C (38°F)46 mm (1.8 inches)86%moderate
May Weather10°C (50°F)60 mm (2.4 inches)75%moderate
June Weather16°C (61°F)71 mm (2.8 inches)75%high
July Weather17°C (63°F)85 mm (3.4 inches)80%high
August Weather16°C (61°F)80 mm (3.2 inches)83%moderate
September Weather11°C (52°F)65 mm (2.6 inches)90%moderate
October Weather6°C (43°F)75 mm (2.9 inches)93%low
November Weather2°C (36°F)52 mm (2.1 inches)94%low
December Weather-2°C (29°F)63 mm (2.5 inches)95%low

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