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September Weather in Kustavi, Finland

Last updated: August 23, 2025

In September, the average temperature in Kustavi, Finland hovers around 13°C (56°F), with a minimum of 6°C (43°F) and a maximum of 21°C (69°F). Expect about 77 mm (3.0 in) of precipitation spread over 12 days, contributing to an overall high average humidity of 86%. Be prepared for a mix of mild days and refreshing rain!

September Temperature in Kustavi

In September in Kustavi, the average temperature is 13°C (56°F), with maximums reaching 21°C (69°F) and minimums dropping as low as 6°C (43°F). This mild climate makes Kustavi an ideal destination for travelers looking to explore comfortably.

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

The chart illustrates September temperature patterns in Kustavi, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Kustavi, September typically has an average temperature of 13°C (56°F), with highs reaching up to 21°C (69°F) and lows dropping to around 6°C (43°F).
JanFebMarAprMayJunJulAugSepOctNovDec322932384657636356484235
Data source: Temperature data for Kustavi 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 Kustavi

In Kustavi in September, the precipitation amount is 77 mm (3.0 in) spread over 12 days.

September Precipitation Trends in Kustavi

The chart displays monthly precipitation patterns in Kustavi, 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 Kustavi, September typically receives around 77 mm (3.0 inches) of precipitation spread over approximately 12 days.
JanFebMarAprMayJunJulAugSepOctNovDec4640402737364767771076987
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Kustavi

In Kustavi in September, humidity is 86%. With an average temperature of 13°C (56°F), this humidity feels like a damp blanket enveloping you, making outdoor activities slightly uncomfortable and prompting travelers to seek shade or air-conditioned spaces frequently.

September Average Humidity in Kustavi

This chart illustrates the average monthly humidity levels in Kustavi, 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 Kustavi is approximately 86%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec92%90%89%85%77%78%78%79%86%90%91%89%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Kustavi

In Kustavi 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 Kustavi for better planning.

Maximum UV Index Levels in Kustavi for September

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

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

This table compares monthly weather conditions in Kustavi, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather0°C (32°F)46 mm (1.8 inches)92%low
February Weather-2°C (29°F)40 mm (1.6 inches)90%low
March Weather0°C (33°F)40 mm (1.6 inches)89%moderate
April Weather3°C (38°F)27 mm (1.1 inches)85%moderate
May Weather8°C (47°F)37 mm (1.5 inches)77%moderate
June Weather14°C (58°F)36 mm (1.4 inches)78%high
July Weather17°C (63°F)47 mm (1.9 inches)78%high
August Weather17°C (63°F)67 mm (2.6 inches)79%moderate
September Weather13°C (56°F)77 mm (3.0 inches)86%moderate
October Weather9°C (48°F)107 mm (4.2 inches)90%low
November Weather5°C (42°F)69 mm (2.7 inches)91%low
December Weather2°C (36°F)87 mm (3.4 inches)89%low

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