September Weather in Iitti, Finland

Last updated: August 23, 2025

In Iitti, Finland, the average temperature in September hovers around 11°C (52°F). During this time, expect temperatures to dip to a minimum of -1°C (31°F) and soar to a maximum of 23°C (73°F). With an average precipitation of 62 mm (2.5 in) across 12 days, don't forget your umbrella! Additionally, the air tends to be quite humid, with an average humidity level of 90%.

September Temperature in Iitti

In September in Iitti, the average temperature is 11°C (52°F). The maximum can reach 23°C (73°F), while the minimum can drop as low as -1°C (31°F). This variation makes it essential to pack layers and be prepared for both warm and cool weather when traveling.

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

The chart illustrates September temperature patterns in Iitti, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Iitti, September typically has an average temperature of 11°C (52°F), with highs reaching up to 23°C (73°F) and lows dropping to around -1°C (31°F).

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

September Precipitation in Iitti

In Iitti in September, the precipitation amount is 62 mm (2.5 in) over the course of 12 days.

September Precipitation Trends in Iitti

The chart displays monthly precipitation patterns in Iitti, 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 Iitti, September typically receives around 62 mm (2.5 inches) of precipitation spread over approximately 12 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 Iitti

In Iitti 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 Iitti

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

In Iitti 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 Iitti, you can check the information here.

Maximum UV Index Levels in Iitti for September

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

Data source: Iitti 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 Iitti Compares to Other Months

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

This table compares monthly weather conditions in Iitti, 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 (25°F)	49 mm (1.9 inches)	98%	low
February Weather	-5°C (24°F)	47 mm (1.9 inches)	96%	low
March Weather	-2°C (29°F)	44 mm (1.7 inches)	93%	moderate
April Weather	3°C (38°F)	46 mm (1.8 inches)	87%	moderate
May Weather	10°C (50°F)	54 mm (2.1 inches)	75%	moderate
June Weather	16°C (61°F)	60 mm (2.3 inches)	74%	high
July Weather	17°C (64°F)	78 mm (3.1 inches)	80%	high
August Weather	16°C (61°F)	86 mm (3.4 inches)	85%	moderate
September Weather	11°C (52°F)	62 mm (2.5 inches)	90%	moderate
October Weather	6°C (43°F)	77 mm (3.0 inches)	94%	low
November Weather	2°C (36°F)	53 mm (2.1 inches)	94%	low
December Weather	-2°C (28°F)	73 mm (2.9 inches)	96%	low