Last updated: August 23, 2025
In September, the average temperature in Viitasaari, Finland hovers around 10°C (50°F). Expect a chill, with minimum temperatures dropping to -2°C (29°F), while the mercury can rise to a pleasant 22°C (72°F) on warmer days. You may experience some drizzle, with 81 mm (3.2 in) of precipitation spread over approximately 14 days. Remember to bring an umbrella, as the average humidity stands at a crisp 91%!
In September in Viitasaari, the average temperature is 10°C (50°F). Maximum temperatures can reach 22°C (72°F), while minimums can dip as low as -2°C (29°F). Travelers should be prepared for a range of weather conditions during this time.
In Viitasaari in September, the precipitation amount is 81 mm (3.2 in) over a span of 14 days.
In Viitasaari in September, humidity is 91%. With an average temperature of 10°C (50°F), this humidity feels like an enveloping dampness that makes traveling a bit uncomfortable, as the moisture clings to your skin and dampens your clothes, soaking up any residual warmth from the cool air.
In Viitasaari 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 Viitasaari, you can check the information here.
UV Risk Categories
Weather in Viitasaari varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Viitasaari, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -6°C (22°F) | 44 mm (1.7 inches) | 99% | low |
| February Weather | -7°C (20°F) | 41 mm (1.6 inches) | 97% | low |
| March Weather | -3°C (27°F) | 38 mm (1.5 inches) | 95% | moderate |
| April Weather | 2°C (35°F) | 44 mm (1.7 inches) | 87% | moderate |
| May Weather | 8°C (47°F) | 61 mm (2.4 inches) | 78% | moderate |
| June Weather | 15°C (60°F) | 57 mm (2.3 inches) | 74% | high |
| July Weather | 17°C (63°F) | 75 mm (3.0 inches) | 80% | high |
| August Weather | 15°C (59°F) | 89 mm (3.5 inches) | 85% | moderate |
| September Weather | 10°C (50°F) | 81 mm (3.2 inches) | 91% | moderate |
| October Weather | 5°C (41°F) | 83 mm (3.3 inches) | 95% | low |
| November Weather | 1°C (33°F) | 64 mm (2.5 inches) | 94% | low |
| December Weather | -4°C (26°F) | 60 mm (2.4 inches) | 98% | low |