September Weather in Riihimaeki, Finland

Last updated: August 23, 2025

In Riihimaeki, Finland, the average temperature in September hovers around 11°C (52°F). However, be prepared for variability, as temperatures can plunge to a chilly -3°C (28°F) or rise to a warm 24°C (75°F). Expect approximately 66 mm (2.6 in) of precipitation over 12 days, accompanied by a notable average humidity of 90%.

September Temperature in Riihimaeki

In September in Riihimaeki, the average temperature is 11°C (52°F). Maximum temperatures can reach 24°C (75°F), while minimums can drop as low as -3°C (28°F). It's advisable to pack layers to prepare for both warm afternoons and chilly evenings.

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

The chart illustrates September temperature patterns in Riihimaeki, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Riihimaeki, September typically has an average temperature of 11°C (52°F), with highs reaching up to 24°C (75°F) and lows dropping to around -3°C (28°F).

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

September Precipitation in Riihimaeki

In Riihimaeki in September, the precipitation amount is 66 mm (2.6 in) over the course of 12 days.

September Precipitation Trends in Riihimaeki

The chart displays monthly precipitation patterns in Riihimaeki, 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 Riihimaeki, September typically receives around 66 mm (2.6 inches) of precipitation spread over approximately 12 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 Riihimaeki

In Riihimaeki in September, humidity is 90%. With an average temperature of 11°C (52°F), this humidity feels like a heavy blanket that clings to your skin, making travel uncomfortable and muggy.

September Average Humidity in Riihimaeki

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

In Riihimaeki 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 Riihimaeki for better planning.

Maximum UV Index Levels in Riihimaeki for September

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

Data source: Riihimaeki 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 Riihimaeki Compares to Other Months

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

This table compares monthly weather conditions in Riihimaeki, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-4°C (26°F)	51 mm (2.0 inches)	97%	low
February Weather	-4°C (24°F)	44 mm (1.7 inches)	95%	low
March Weather	-1°C (30°F)	46 mm (1.8 inches)	93%	moderate
April Weather	4°C (39°F)	46 mm (1.8 inches)	86%	moderate
May Weather	10°C (51°F)	58 mm (2.3 inches)	75%	moderate
June Weather	16°C (62°F)	65 mm (2.5 inches)	75%	high
July Weather	17°C (64°F)	82 mm (3.2 inches)	80%	high
August Weather	16°C (61°F)	77 mm (3.0 inches)	83%	moderate
September Weather	11°C (52°F)	66 mm (2.6 inches)	90%	moderate
October Weather	6°C (43°F)	77 mm (3.0 inches)	93%	low
November Weather	2°C (36°F)	53 mm (2.1 inches)	94%	low
December Weather	-2°C (29°F)	67 mm (2.6 inches)	95%	low