Last updated: August 23, 2025
In September, the average temperature in Posio, Finland is a cool 7°C (46°F). Visitors can experience a range of temperatures, with a minimum dipping to -5°C (23°F) and a pleasant maximum reaching 21°C (71°F). Precipitation averages 82 mm (3.2 in) over 14 days, and the air is quite moist, boasting an average humidity of 91%. Perfect for those who enjoy a brisk, refreshing climate!
In September in Posio, the average temperature is 7°C (46°F), with maximums reaching 21°C (71°F) and minimums dipping as low as -5°C (23°F). This varied weather makes it important to pack layers and be prepared for both warmth and chill while exploring the region.
In Posio in September, the precipitation amount is 82 mm (3.2 in) spread over 14 days.
In Posio in September humidity is 91%. With an average temperature of 7°C (46°F), this humidity feels like a damp chill that seeps into your bones, making outdoor activities feel less invigorating and more exhausting, as the heavy air clings to your skin and makes every breath feel thicker.
In Posio 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 Posio, you can check the information here.
UV Risk Categories
Weather in Posio varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Posio, focusing on differences in temperature, rainfall, humidity, and UV levels.
Temperature | Precipitation | Humidity | UV | |
---|---|---|---|---|
January Weather | -10°C (14°F) | 43 mm (1.7 inches) | 101% | low |
February Weather | -10°C (14°F) | 40 mm (1.6 inches) | 99% | low |
March Weather | -6°C (21°F) | 44 mm (1.7 inches) | 94% | low |
April Weather | 0°C (32°F) | 43 mm (1.7 inches) | 88% | moderate |
May Weather | 5°C (41°F) | 49 mm (1.9 inches) | 83% | moderate |
June Weather | 12°C (55°F) | 85 mm (3.4 inches) | 79% | high |
July Weather | 15°C (60°F) | 76 mm (3.0 inches) | 83% | high |
August Weather | 12°C (55°F) | 110 mm (4.3 inches) | 87% | moderate |
September Weather | 7°C (46°F) | 82 mm (3.2 inches) | 91% | moderate |
October Weather | 2°C (35°F) | 82 mm (3.2 inches) | 96% | low |
November Weather | -3°C (27°F) | 71 mm (2.8 inches) | 96% | low |
December Weather | -7°C (20°F) | 58 mm (2.3 inches) | 100% | low |