September Weather in Sumiainen, Finland

Last updated: August 23, 2025

In Sumiainen, Finland, the average temperature in September hovers around 10°C (50°F). While temperatures can dip as low as -2°C (30°F), they can also reach a warm 22°C (72°F). Expect some wet weather, with an average precipitation of 80 mm (3.2 in) over 13 days. Humidity remains high at an average of 91%, creating a uniquely moist atmosphere.

September Temperature in Sumiainen

In September in Sumiainen, the average temperature is 10°C (50°F). Maximums can reach 22°C (72°F), while minimums can dip as low as -2°C (30°F). Be prepared for a wide range of temperatures during your travels, so pack accordingly!

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

The chart illustrates September temperature patterns in Sumiainen, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Sumiainen, September typically has an average temperature of 10°C (50°F), with highs reaching up to 22°C (72°F) and lows dropping to around -2°C (30°F).

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

September Precipitation in Sumiainen

In Sumiainen in September, the precipitation amount is 80 mm (3.2 in) spread over 13 days.

September Precipitation Trends in Sumiainen

The chart displays monthly precipitation patterns in Sumiainen, 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 Sumiainen, September typically receives around 80 mm (3.2 inches) of precipitation spread over approximately 13 days.

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

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

September Humidity in Sumiainen

In Sumiainen in September, humidity is 91%. With an average temperature of 10°C (50°F), this humidity feels like an enveloping dampness that makes traveling a bit uncomfortable, as the moisture clings to your skin and dampens your clothes, soaking up any residual warmth from the cool air.

September Average Humidity in Sumiainen

This chart illustrates the average monthly humidity levels in Sumiainen, 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 Sumiainen is approximately 91%, 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 Sumiainen

In Sumiainen 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 Sumiainen, you can check the information here.

Maximum UV Index Levels in Sumiainen for September

The chart shows the monthly maximum UV Index (UVI) for Sumiainen 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 Sumiainen typically reaches 3, which falls under the moderate exposure category.

Data source: Sumiainen 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 Sumiainen Compares to Other Months

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

This table compares monthly weather conditions in Sumiainen, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-6°C (22°F)	45 mm (1.8 inches)	99%	low
February Weather	-6°C (21°F)	41 mm (1.6 inches)	97%	low
March Weather	-3°C (27°F)	38 mm (1.5 inches)	95%	moderate
April Weather	2°C (35°F)	43 mm (1.7 inches)	87%	moderate
May Weather	8°C (48°F)	60 mm (2.4 inches)	78%	moderate
June Weather	15°C (60°F)	57 mm (2.3 inches)	74%	high
July Weather	17°C (63°F)	71 mm (2.8 inches)	80%	high
August Weather	15°C (60°F)	89 mm (3.5 inches)	85%	moderate
September Weather	10°C (50°F)	80 mm (3.2 inches)	91%	moderate
October Weather	5°C (41°F)	80 mm (3.1 inches)	95%	low
November Weather	1°C (34°F)	62 mm (2.4 inches)	94%	low
December Weather	-3°C (26°F)	62 mm (2.4 inches)	98%	low