Last updated: June 24, 2025
In Central Valley, United States during December, the average temperature hovers around -4°C (25°F). Expect chilly conditions, with minimum temperatures plummeting to -24°C (-11°F) and occasional spikes reaching up to 13°C (56°F). You'll encounter about 40 mm (1.6 in) of precipitation distributed across 9 days, and the average humidity sits at a high 87%, making it a notably brisk and damp time of year.
In December in Central Valley, the average temperature is -4°C (25°F), with maximums reaching 13°C (56°F) and minimums dropping as low as -24°C (-11°F). Travelers should be prepared for a wide temperature range, making warm clothing essential for outdoor activities.
In Central Valley in December, the precipitation amount is 40 mm (1.6 in) over the course of 9 days.
In Central Valley in December humidity is 87%. With an average temperature of -4°C (25°F), this humidity feels like a biting chill that clings to your skin, making every step outside feel like an endeavor as the cold damp air numbs your senses and weighs you down, creating an atmosphere that is both invigorating and challenging for traveling.
In Central Valley in December, the maximum UV index reaches 4, which corresponds to a moderate Exposure Category. With a time to burn of 30 minutes, it’s important to take precautions to protect your skin. You can find more details in the Hourly UV Index in Central Valley for better planning.
UV Risk Categories
Weather in Central Valley varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Central Valley, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -5°C (23°F) | 42 mm (1.6 inches) | 87% | moderate |
| February Weather | -4°C (26°F) | 55 mm (2.2 inches) | 88% | high |
| March Weather | 0°C (33°F) | 59 mm (2.3 inches) | 77% | very high |
| April Weather | 5°C (42°F) | 46 mm (1.8 inches) | 69% | extreme |
| May Weather | 11°C (52°F) | 44 mm (1.7 inches) | 54% | extreme |
| June Weather | 19°C (66°F) | 8 mm (0.3 inches) | 45% | extreme |
| July Weather | 22°C (72°F) | 21 mm (0.8 inches) | 37% | extreme |
| August Weather | 21°C (71°F) | 20 mm (0.8 inches) | 34% | extreme |
| September Weather | 16°C (61°F) | 23 mm (0.9 inches) | 47% | very high |
| October Weather | 7°C (44°F) | 36 mm (1.4 inches) | 67% | high |
| November Weather | 2°C (37°F) | 27 mm (1.1 inches) | 82% | high |
| December Weather | -4°C (25°F) | 40 mm (1.6 inches) | 87% | moderate |