September Weather in Kotka, Finland

Last updated: August 23, 2025

In Kotka, Finland, the average temperature in September hovers around 12°C (54°F). Expect a chilly minimum of 0°C (33°F) and a pleasant maximum of 22°C (71°F). With 66 mm (2.6 in) of precipitation spread over 13 days, you might want to keep an umbrella handy! Average humidity sits at a high 90%, adding to the invigorating atmosphere of the season.

September Temperature in Kotka

In September in Kotka, the average temperature is 12°C (54°F). Maximum temperatures can reach 22°C (71°F), while minimums can drop as low as 0°C (33°F). This varied climate makes it essential for travelers to pack layers to comfortably enjoy their stay.

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

The chart illustrates September temperature patterns in Kotka, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Kotka, September typically has an average temperature of 12°C (54°F), with highs reaching up to 22°C (71°F) and lows dropping to around 0°C (33°F).

Data source: Temperature data for Kotka generated using information from the Copernicus Climate Change Service.

September Precipitation in Kotka

In Kotka in September, the total precipitation amount is 66 mm (2.6 in) spread over the course of 13 days.

September Precipitation Trends in Kotka

The chart displays monthly precipitation patterns in Kotka, 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 Kotka, September typically receives around 66 mm (2.6 inches) of precipitation spread over approximately 13 days.

Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

September Humidity in Kotka

In Kotka 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 Kotka

This chart illustrates the average monthly humidity levels in Kotka, 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 Kotka is approximately 90%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Kotka

In Kotka 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 Kotka for better planning.

Maximum UV Index Levels in Kotka for September

The chart shows the monthly maximum UV Index (UVI) for Kotka 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 Kotka typically reaches 4, which falls under the moderate exposure category.

Data source: Kotka 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 Kotka Compares to Other Months

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

This table compares monthly weather conditions in Kotka, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-3°C (27°F)	55 mm (2.2 inches)	98%	low
February Weather	-4°C (25°F)	55 mm (2.2 inches)	96%	low
March Weather	-1°C (30°F)	49 mm (1.9 inches)	93%	moderate
April Weather	4°C (39°F)	43 mm (1.7 inches)	87%	moderate
May Weather	10°C (50°F)	48 mm (1.9 inches)	75%	moderate
June Weather	16°C (61°F)	48 mm (1.9 inches)	74%	high
July Weather	18°C (64°F)	75 mm (3.0 inches)	80%	high
August Weather	17°C (62°F)	88 mm (3.5 inches)	85%	moderate
September Weather	12°C (54°F)	66 mm (2.6 inches)	90%	moderate
October Weather	7°C (45°F)	86 mm (3.4 inches)	94%	low
November Weather	3°C (38°F)	66 mm (2.6 inches)	94%	low
December Weather	-1°C (30°F)	81 mm (3.2 inches)	96%	low