Last updated: June 24, 2025
In Union City, United States, the average temperature in December hovers around 7°C (45°F). However, temperatures can range significantly, with a minimum of -11°C (13°F) and a soaring maximum of 24°C (75°F). Expect about 117 mm (4.6 in) of precipitation over approximately 9 days, coupled with a high average humidity of 88%.
In December in Union City, the average temperature is 7°C (45°F). The maximum can reach 24°C (75°F), while the minimum can drop to as low as -11°C (13°F). It’s a month of varied temperatures, so travelers should pack layers to accommodate both the warmth of the day and the chill of the night.
In Union City in December, the total precipitation amount is 117 mm (4.6 in) spread over a period of 9 days.
In Union City in December humidity is 88%. With an average temperature of 7°C (45°F), this humidity feels like a damp chill that seeps into your bones, making traveling uncomfortable as you navigate through a heavy, thick atmosphere that clings to your skin.
In Union City in December, 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 Union City, you can check the information here.
UV Risk Categories
Weather in Union City varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Union City, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 4°C (39°F) | 105 mm (4.1 inches) | 86% | moderate |
| February Weather | 6°C (43°F) | 161 mm (6.3 inches) | 84% | high |
| March Weather | 11°C (52°F) | 173 mm (6.8 inches) | 84% | high |
| April Weather | 15°C (59°F) | 145 mm (5.7 inches) | 80% | very high |
| May Weather | 21°C (71°F) | 124 mm (4.9 inches) | 82% | extreme |
| June Weather | 25°C (78°F) | 109 mm (4.3 inches) | 83% | extreme |
| July Weather | 27°C (81°F) | 113 mm (4.5 inches) | 79% | extreme |
| August Weather | 26°C (79°F) | 97 mm (3.8 inches) | 76% | very high |
| September Weather | 24°C (75°F) | 86 mm (3.4 inches) | 75% | very high |
| October Weather | 17°C (63°F) | 113 mm (4.4 inches) | 74% | high |
| November Weather | 9°C (48°F) | 104 mm (4.1 inches) | 85% | moderate |
| December Weather | 7°C (45°F) | 117 mm (4.6 inches) | 88% | moderate |