Last updated: August 23, 2025
In Siuntio, Finland, the average temperature for December hovers around -1°C (31°F), with extremes ranging from a chilly -18°C (0°F) to a mild 7°C (44°F). Expect around 75 mm (2.9 in) of precipitation over approximately 15 days, and be prepared for high humidity levels at 95%.
In December in Siuntio, the average temperature is -1°C (31°F). Maximum temperatures can reach 7°C (44°F), while the minimum can drop as low as -18°C (0°F). Travelers should be prepared for chilly weather and dress in layers to stay warm during their visit.
In Siuntio in December, the precipitation amount is 75 mm (2.9 in) over a span of 15 days.
In Siuntio in December, humidity is 95%. With an average temperature of -1°C (31°F), this humidity feels like an icy weight on your skin, making travel uncomfortable and every breath a challenge as the cold dampness clings to your clothes.
In Siuntio in December, the maximum UV index is 1, which corresponds to a low Exposure Category. This means you have a time to burn of 45 minutes. For more details, you can check the Hourly UV Index in Siuntio.
UV Risk Categories
Weather in Siuntio varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Siuntio, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -2°C (28°F) | 58 mm (2.3 inches) | 97% | low |
| February Weather | -3°C (26°F) | 49 mm (1.9 inches) | 95% | low |
| March Weather | -1°C (31°F) | 54 mm (2.1 inches) | 93% | moderate |
| April Weather | 3°C (39°F) | 40 mm (1.6 inches) | 86% | moderate |
| May Weather | 10°C (50°F) | 53 mm (2.1 inches) | 75% | moderate |
| June Weather | 16°C (61°F) | 51 mm (2.0 inches) | 75% | high |
| July Weather | 18°C (64°F) | 83 mm (3.3 inches) | 80% | high |
| August Weather | 16°C (62°F) | 78 mm (3.1 inches) | 83% | moderate |
| September Weather | 12°C (54°F) | 65 mm (2.6 inches) | 90% | moderate |
| October Weather | 7°C (45°F) | 88 mm (3.5 inches) | 93% | low |
| November Weather | 3°C (38°F) | 63 mm (2.5 inches) | 94% | low |
| December Weather | -1°C (31°F) | 75 mm (2.9 inches) | 95% | low |