Last updated: June 24, 2025
In December, the average temperature in Rock Island, United States hovers around 8°C (47°F), with a notable range from a chilly -7°C (20°F) to a warm 26°C (79°F). Expect around 85 mm (3.3 in) of precipitation spread over 8 days, coupled with a high average humidity of 87%. Perfect for cozy indoor activities or exploring the vibrant local culture!
In December in Rock Island, the average temperature is 8°C (47°F), with maximums reaching 26°C (79°F) and minimums dropping as low as -7°C (20°F). Be prepared for a wide range of temperatures when traveling to Rock Island during this month.
In Rock Island in December, the precipitation amount is 85 mm (3.3 in) over the course of 8 days.
In Rock Island in December, humidity is 87%. With an average temperature of 8°C (47°F), this humidity feels like a damp chill that clings to your skin, making outdoor exploration uncomfortably muggy despite the cool air.
In Rock Island 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 Rock Island for better planning.
UV Risk Categories
Weather in Rock Island varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Rock Island, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 5°C (42°F) | 83 mm (3.3 inches) | 82% | moderate |
| February Weather | 7°C (45°F) | 113 mm (4.5 inches) | 79% | high |
| March Weather | 13°C (56°F) | 119 mm (4.7 inches) | 77% | high |
| April Weather | 16°C (61°F) | 135 mm (5.3 inches) | 78% | very high |
| May Weather | 22°C (71°F) | 200 mm (7.9 inches) | 82% | extreme |
| June Weather | 26°C (79°F) | 87 mm (3.4 inches) | 81% | extreme |
| July Weather | 28°C (83°F) | 80 mm (3.1 inches) | 75% | extreme |
| August Weather | 27°C (81°F) | 116 mm (4.6 inches) | 61% | very high |
| September Weather | 25°C (77°F) | 66 mm (2.6 inches) | 59% | very high |
| October Weather | 18°C (64°F) | 131 mm (5.2 inches) | 69% | high |
| November Weather | 11°C (52°F) | 69 mm (2.7 inches) | 82% | moderate |
| December Weather | 8°C (47°F) | 85 mm (3.3 inches) | 87% | moderate |