Last updated: August 27, 2025
In December, the average temperature in Onsala, Sweden hovers around 3°C (37°F), with fluctuations from a brisk -10°C (15°F) to a mild 10°C (51°F). Expect 78 mm (3.1 in) of precipitation spread over 15 days, contributing to an average humidity of a damp 91%. Whether you're braving the chill or enjoying occasional warmth, be prepared for a varied and atmospheric experience!
In December in Onsala, the average temperature is 3°C (37°F). Maximums can reach 10°C (51°F), while minimums can drop as low as -10°C (15°F). Be prepared for chilly weather and dress warmly if you plan to visit during this time.
In Onsala, in December, the precipitation amount is 78 mm (3.1 in) over a span of 15 days.
In Onsala in December, humidity is 91%. With an average temperature of 3°C (37°F), this humidity feels like a damp chill that seeps into your bones, making travel quite uncomfortable and requiring you to dress in layers to stay warm while battling the oppressive mugginess.
In Onsala 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 Onsala.
UV Risk Categories
Weather in Onsala varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Onsala, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 2°C (36°F) | 53 mm (2.1 inches) | 92% | low |
| February Weather | 1°C (35°F) | 70 mm (2.7 inches) | 91% | low |
| March Weather | 3°C (38°F) | 65 mm (2.6 inches) | 89% | moderate |
| April Weather | 7°C (45°F) | 38 mm (1.5 inches) | 84% | moderate |
| May Weather | 12°C (53°F) | 69 mm (2.7 inches) | 75% | high |
| June Weather | 17°C (62°F) | 61 mm (2.4 inches) | 73% | high |
| July Weather | 18°C (64°F) | 78 mm (3.1 inches) | 73% | high |
| August Weather | 17°C (63°F) | 111 mm (4.4 inches) | 77% | high |
| September Weather | 14°C (57°F) | 99 mm (3.9 inches) | 85% | moderate |
| October Weather | 10°C (50°F) | 106 mm (4.2 inches) | 91% | low |
| November Weather | 6°C (43°F) | 72 mm (2.8 inches) | 92% | low |
| December Weather | 3°C (37°F) | 78 mm (3.1 inches) | 91% | low |