September Weather in Interlaken, United States

Last updated: June 24, 2025

In Interlaken, United States, the average temperature in September hovers around 21°C (71°F), making it a pleasant time to visit. Expect minimum temperatures of 11°C (51°F) and highs reaching up to 31°C (87°F). With an average humidity of 68% and about 102 mm (4.0 in) of rainfall spread over 10 days, this month presents a refreshing climate with occasional showers. Embrace the varied weather that enhances the region's charm!

September Temperature in Interlaken

In September in Interlaken, the average temperature is 21°C (71°F). Maximum can reach 31°C (87°F) and minimum can be as low as 11°C (51°F). This pleasant climate makes Interlaken an ideal destination for travelers seeking a comfortable getaway during this time.

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

The chart illustrates September temperature patterns in Interlaken, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Interlaken, September typically has an average temperature of 21°C (71°F), with highs reaching up to 31°C (87°F) and lows dropping to around 11°C (51°F).

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

September Precipitation in Interlaken

In Interlaken in September, the total precipitation amount is 102 mm (4.0 in) falling over the course of 10 days.

September Precipitation Trends in Interlaken

The chart displays monthly precipitation patterns in Interlaken, 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 Interlaken, September typically receives around 102 mm (4.0 inches) of precipitation spread over approximately 10 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 Interlaken

In Interlaken in September, humidity is 68%. With an average temperature of 21°C (71°F), this humidity feels like a warm embrace, making traveling a bit sticky but also inviting for leisurely strolls and outdoor adventures.

September Average Humidity in Interlaken

This chart illustrates the average monthly humidity levels in Interlaken, 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 Interlaken is approximately 68%, 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 Interlaken

In Interlaken in September, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in Interlaken.

Maximum UV Index Levels in Interlaken for September

The chart shows the monthly maximum UV Index (UVI) for Interlaken 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 Interlaken typically reaches 8, which falls under the very high exposure category.

Data source: Interlaken 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 Interlaken Compares to Other Months

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

This table compares monthly weather conditions in Interlaken, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	2°C (37°F)	78 mm (3.1 inches)	84%	moderate
February Weather	4°C (39°F)	129 mm (5.1 inches)	82%	moderate
March Weather	6°C (43°F)	109 mm (4.3 inches)	81%	high
April Weather	11°C (51°F)	124 mm (4.9 inches)	78%	very high
May Weather	15°C (60°F)	129 mm (5.1 inches)	69%	very high
June Weather	21°C (70°F)	89 mm (3.5 inches)	69%	very high
July Weather	25°C (77°F)	129 mm (5.1 inches)	62%	very high
August Weather	24°C (76°F)	126 mm (4.9 inches)	65%	very high
September Weather	21°C (71°F)	102 mm (4.0 inches)	68%	very high
October Weather	17°C (62°F)	153 mm (6.0 inches)	74%	high
November Weather	9°C (49°F)	100 mm (3.9 inches)	82%	moderate
December Weather	5°C (41°F)	127 mm (5.0 inches)	80%	low