Last updated: June 24, 2025
In December, the average temperature in Castalia, United States hovers around 2°C (35°F). Expect chilly days, with a minimum dropping as low as -16°C (4°F) and a maximum reaching 15°C (59°F). This month also sees about 72 mm (2.8 in) of precipitation spread over 12 days, contributing to a high average humidity of 86%. Prepare accordingly for a brisk and damp winter experience!
In December in Castalia, the average temperature is 2°C (35°F). Maximums can reach 15°C (59°F), and minimums can be as low as -16°C (4°F). Be sure to pack warm clothing and prepare for variable weather if you plan to visit during this time.
In Castalia in December, the total precipitation amount is 72 mm (2.8 in) over the course of 12 days.
In Castalia in December humidity is 86%. With an average temperature of 2°C (35°F), this humidity feels like a damp chill that seeps into your bones, making traveling quite uncomfortable as your clothes cling to you and the cold air cuts through any warmth you try to find.
In Castalia 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 Castalia, you can visit Hourly UV Index in Castalia.
UV Risk Categories
Weather in Castalia varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Castalia, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -1°C (30°F) | 76 mm (3.0 inches) | 88% | moderate |
| February Weather | -1°C (31°F) | 83 mm (3.3 inches) | 87% | moderate |
| March Weather | 3°C (39°F) | 87 mm (3.4 inches) | 87% | high |
| April Weather | 9°C (48°F) | 106 mm (4.2 inches) | 87% | very high |
| May Weather | 16°C (60°F) | 124 mm (4.9 inches) | 81% | very high |
| June Weather | 21°C (71°F) | 108 mm (4.3 inches) | 82% | very high |
| July Weather | 24°C (76°F) | 121 mm (4.8 inches) | 81% | very high |
| August Weather | 23°C (74°F) | 82 mm (3.2 inches) | 78% | very high |
| September Weather | 20°C (69°F) | 70 mm (2.8 inches) | 78% | very high |
| October Weather | 14°C (58°F) | 99 mm (3.9 inches) | 82% | high |
| November Weather | 6°C (42°F) | 98 mm (3.9 inches) | 89% | moderate |
| December Weather | 2°C (35°F) | 72 mm (2.8 inches) | 86% | low |