Last updated: March 2, 2024
The weather in Helsinki, Finland, during September is characterized by an average temperature of 12°C (54°F). Highs can soar to 21°C (69°F), while lows may dip to 2°C (36°F). Typically, the humidity level in Helsinki throughout September hovers around 90%.
Minimum temperature
Average temperature
Maximum temperature
Humidity
In September, Helsinki averages 76 mm (3.0 inches) of rainfall, typically over the course of 13 rainy days. The month enjoys an average of 12 hours 48 minutes of daylight, with the sun shining for approximately 9 hours 39 minutes each day. Additionally, there is a 28% probability of sunny days during this period.
Precipitation
Rainy days
Sunshine hours
Chance of sun
In September, the UV Index in Helsinki reaches a maximum of 4, indicating a level of Moderate exposure. The most intense UV radiation typically occurs between 13:00 and 15:00, during which unprotected skin may burn in as little as 30 minutes.
| 07:00 | 08:00 | 09:00 | 10:00 | 11:00 | 12:00 | 13:00 | 14:00 | 15:00 | 16:00 | 17:00 | 18:00 | 19:00 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UVI | 1 | 1 | 1 | 2 | 3 | 3 | 4 | 3 | 3 | 2 | 2 | 1 | 1 |
| Exposure | Low | Moderate | Low | ||||||||||
| Time to burn | 45 min | 30 min | 45 min | ||||||||||