Last updated: June 24, 2025
In December, the average temperature in Swansea, United States hovers around 2°C (36°F). This chilly month can see temperatures plummet to a minimum of -15°C (5°F), while the mercury might rise to a maximum of 17°C (63°F). Expect 10 days of rain, accumulating about 120 mm (4.7 in) of precipitation and an average humidity level of 80%—perfect for cozy indoor activities!
In December in Swansea, the average temperature is 2°C (36°F). Maximums can reach 17°C (63°F), while minimums can plummet to as low as -15°C (5°F). Travelers should be prepared for a wide range of temperatures and dress accordingly to ensure comfort during their stay.
In Swansea in December, the precipitation amount is 120 mm (4.7 in) spread over a duration of 10 days.
In Swansea in December humidity is 80%. With an average temperature of 2°C (36°F), this humidity feels like a heavy, damp chill that seeps into your bones, making it challenging for outdoor adventures and often necessitating layered clothing to stay warm and comfortable while exploring.
In Swansea in December, the maximum UV index is 2, which corresponds to a low exposure category. With this level of UV radiation, the time to burn is approximately 45 minutes. To learn more about the hourly UV index in Swansea, you can visit Hourly UV Index in Swansea.
UV Risk Categories
Weather in Swansea varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Swansea, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 0°C (33°F) | 74 mm (2.9 inches) | 84% | moderate |
| February Weather | 1°C (35°F) | 92 mm (3.6 inches) | 84% | moderate |
| March Weather | 4°C (39°F) | 102 mm (4.0 inches) | 82% | high |
| April Weather | 9°C (49°F) | 123 mm (4.9 inches) | 79% | very high |
| May Weather | 15°C (58°F) | 101 mm (4.0 inches) | 75% | very high |
| June Weather | 20°C (68°F) | 97 mm (3.8 inches) | 78% | very high |
| July Weather | 23°C (74°F) | 122 mm (4.8 inches) | 76% | very high |
| August Weather | 23°C (74°F) | 92 mm (3.6 inches) | 76% | very high |
| September Weather | 19°C (67°F) | 97 mm (3.8 inches) | 75% | very high |
| October Weather | 14°C (57°F) | 135 mm (5.3 inches) | 75% | high |
| November Weather | 7°C (45°F) | 101 mm (4.0 inches) | 80% | moderate |
| December Weather | 2°C (36°F) | 120 mm (4.7 inches) | 80% | low |