Last updated: June 24, 2025
In September, the average temperature in Interlaken, United States is a pleasant 18°C (64°F). However, temperatures can fluctuate, with a minimum of 2°C (36°F) and a maximum of 33°C (92°F). Expect some rain, as the area receives an average precipitation of 82 mm (3.2 in) over 8 days. With an average humidity of 78%, be prepared for a comfortably humid climate!
In September in Interlaken, the average temperature is 18°C (64°F), with maximums reaching 33°C (92°F) and minimums dropping as low as 2°C (36°F). This diverse temperature range makes Interlaken an ideal destination for travelers seeking both warm and cooler experiences during their visit.
In Interlaken in September, the total precipitation amount reached 82 mm (3.2 in) over the course of 8 days.
In Interlaken in September, humidity is 78%. With an average temperature of 18°C (64°F), this humidity feels like a warm, thick blanket wrapping around you, making traveling feel a bit sticky and sluggish, yet the coolness of the air tempers the intensity, inviting you to explore at a leisurely pace.
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.
UV Risk Categories
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.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -3°C (27°F) | 76 mm (3.0 inches) | 90% | moderate |
| February Weather | -2°C (28°F) | 85 mm (3.4 inches) | 90% | moderate |
| March Weather | 1°C (35°F) | 80 mm (3.2 inches) | 87% | high |
| April Weather | 8°C (46°F) | 111 mm (4.4 inches) | 88% | very high |
| May Weather | 14°C (58°F) | 119 mm (4.7 inches) | 82% | very high |
| June Weather | 19°C (67°F) | 90 mm (3.5 inches) | 79% | very high |
| July Weather | 22°C (72°F) | 135 mm (5.3 inches) | 78% | very high |
| August Weather | 21°C (71°F) | 86 mm (3.4 inches) | 76% | very high |
| September Weather | 18°C (64°F) | 82 mm (3.2 inches) | 78% | very high |
| October Weather | 12°C (54°F) | 144 mm (5.7 inches) | 84% | high |
| November Weather | 4°C (39°F) | 89 mm (3.5 inches) | 89% | moderate |
| December Weather | 0°C (32°F) | 91 mm (3.6 inches) | 86% | low |