September Weather in Siilinjaervi, Finland

Last updated: August 23, 2025

In Siilinjaervi, Finland, the average temperature in September typically hovers around 10°C (50°F). Expect a chilly minimum of -1°C (30°F), with a warmer maximum reaching 23°C (74°F). Be prepared for 91 mm (3.6 in) of precipitation spread over 14 days, accompanied by a high average humidity of 92%.

September Temperature in Siilinjaervi

In September in Siilinjaervi, the average temperature is 10°C (50°F). Maximums can reach 23°C (74°F), and minimums can be as low as -1°C (30°F). Be prepared for a range of weather conditions if you're planning to travel during this month.

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

The chart illustrates September temperature patterns in Siilinjaervi, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Siilinjaervi, September typically has an average temperature of 10°C (50°F), with highs reaching up to 23°C (74°F) and lows dropping to around -1°C (30°F).

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

September Precipitation in Siilinjaervi

In Siilinjaervi in September, the precipitation amount is 91 mm (3.6 in) over a span of 14 days.

September Precipitation Trends in Siilinjaervi

The chart displays monthly precipitation patterns in Siilinjaervi, 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 Siilinjaervi, September typically receives around 91 mm (3.6 inches) of precipitation spread over approximately 14 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 Siilinjaervi

In Siilinjaervi in September humidity is 92%. With an average temperature of 10°C (50°F), this humidity feels like a chilly, damp cloak wrapping around you, making every step outside feel heavy and each breath a bit more labored, turning exploring into an uncomfortable challenge.

September Average Humidity in Siilinjaervi

This chart illustrates the average monthly humidity levels in Siilinjaervi, 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 Siilinjaervi is approximately 92%, 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 Siilinjaervi

In Siilinjaervi 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 Siilinjaervi, you can check the information here.

Maximum UV Index Levels in Siilinjaervi for September

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

Data source: Siilinjaervi 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 Siilinjaervi Compares to Other Months

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

This table compares monthly weather conditions in Siilinjaervi, 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 (21°F)	49 mm (1.9 inches)	99%	low
February Weather	-7°C (19°F)	43 mm (1.7 inches)	98%	low
March Weather	-3°C (26°F)	43 mm (1.7 inches)	95%	moderate
April Weather	2°C (35°F)	42 mm (1.6 inches)	87%	moderate
May Weather	8°C (47°F)	56 mm (2.2 inches)	78%	moderate
June Weather	15°C (60°F)	66 mm (2.6 inches)	75%	high
July Weather	17°C (64°F)	84 mm (3.3 inches)	83%	high
August Weather	15°C (60°F)	103 mm (4.0 inches)	88%	moderate
September Weather	10°C (50°F)	91 mm (3.6 inches)	92%	moderate
October Weather	5°C (41°F)	84 mm (3.3 inches)	95%	low
November Weather	1°C (33°F)	77 mm (3.0 inches)	94%	low
December Weather	-4°C (25°F)	68 mm (2.7 inches)	98%	low