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September Weather in Vantaa, Finland

Last updated: August 23, 2025

In September, the average temperature in Vantaa, Finland hovers around 12°C (54°F). Expect minimums of -1°C (31°F) and maximums reaching 23°C (73°F). During this time, prepare for precipitation totaling 76 mm (3.0 in) spread over approximately 13 days, accompanied by a high average humidity of 90%.

September Temperature in Vantaa

In September in Vantaa, the average temperature is 12°C (54°F). The maximum can reach 23°C (73°F) and the minimum can be as low as -1°C (31°F). It's a great time to explore the area's outdoor activities and pack accordingly for varying weather conditions.

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

The chart illustrates September temperature patterns in Vantaa, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Vantaa, September typically has an average temperature of 12°C (54°F), with highs reaching up to 23°C (73°F) and lows dropping to around -1°C (31°F).
JanFebMarAprMayJunJulAugSepOctNovDec272630395061646254453830
Data source: Temperature data for Vantaa 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 Vantaa

In Vantaa in September, the total precipitation amount is 76 mm (3.0 in), which occurs over the course of 13 days.

September Precipitation Trends in Vantaa

The chart displays monthly precipitation patterns in Vantaa, 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 Vantaa, September typically receives around 76 mm (3.0 inches) of precipitation spread over approximately 13 days.
JanFebMarAprMayJunJulAugSepOctNovDec554852485661918376896273
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Vantaa

In Vantaa in September, humidity is 90%. With an average temperature of 12°C (54°F), this humidity feels like a damp chill that clings to your skin, making outdoor activities uncomfortable and traveling a bit more draining than usual.

September Average Humidity in Vantaa

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

In Vantaa in September, the maximum UV index reaches 4, which corresponds to a moderate Exposure Category. With a time to burn of 30 minutes, it’s important to take precautions to protect your skin. You can find more details in the Hourly UV Index in Vantaa for better planning.

Maximum UV Index Levels in Vantaa for September

The chart shows the monthly maximum UV Index (UVI) for Vantaa 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 Vantaa typically reaches 4, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec113457754211
Data source: Vantaa 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 Vantaa Compares to Other Months

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

This table compares monthly weather conditions in Vantaa, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-3°C (28°F)55 mm (2.2 inches)97%low
February Weather-3°C (26°F)48 mm (1.9 inches)95%low
March Weather-1°C (31°F)52 mm (2.0 inches)93%moderate
April Weather4°C (39°F)48 mm (1.9 inches)86%moderate
May Weather10°C (50°F)56 mm (2.2 inches)75%moderate
June Weather16°C (62°F)61 mm (2.4 inches)75%high
July Weather18°C (65°F)91 mm (3.6 inches)80%high
August Weather17°C (62°F)83 mm (3.3 inches)83%moderate
September Weather12°C (54°F)76 mm (3.0 inches)90%moderate
October Weather7°C (45°F)89 mm (3.5 inches)93%low
November Weather3°C (38°F)62 mm (2.5 inches)94%low
December Weather-1°C (31°F)73 mm (2.9 inches)95%low

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