Last updated: June 24, 2025
In Harrisburg, United States, the average temperature in December hovers around -3°C (26°F), with extremes ranging from a frigid -23°C (-10°F) to a mild 16°C (60°F). Expect approximately 39 mm (1.5 in) of precipitation spread over 4 days, and prepare for a notably high 83% humidity that can make the cold feel even more biting.
In December in Harrisburg, the average temperature is -3°C (26°F). Maximum temperatures can reach 16°C (60°F), while minimums can plunge to as low as -23°C (-10°F). Be prepared for a winter wonderland, as the weather can vary greatly, making it essential to pack accordingly for your travels.
In Harrisburg in December, the precipitation amount is 39 mm (1.5 in) spread over a period of 4 days.
In Harrisburg in December, humidity is 83%. With an average temperature of -3°C (26°F), this humidity feels like a heavy blanket of cold air enveloping you, making it challenging to stay warm while traveling. The dampness seeps into your clothing, creating an uncomfortable chill that lingers even indoors, often requiring extra layers and careful planning for outdoor activities.
In Harrisburg 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 Harrisburg, you can visit Hourly UV Index in Harrisburg.
UV Risk Categories
Weather in Harrisburg varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Harrisburg, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -7°C (20°F) | 21 mm (0.8 inches) | 80% | low |
| February Weather | -7°C (20°F) | 24 mm (0.9 inches) | 84% | moderate |
| March Weather | 2°C (35°F) | 65 mm (2.6 inches) | 75% | moderate |
| April Weather | 7°C (45°F) | 82 mm (3.2 inches) | 79% | very high |
| May Weather | 15°C (59°F) | 128 mm (5.0 inches) | 74% | very high |
| June Weather | 23°C (73°F) | 85 mm (3.3 inches) | 81% | extreme |
| July Weather | 24°C (75°F) | 77 mm (3.0 inches) | 82% | very high |
| August Weather | 22°C (72°F) | 94 mm (3.7 inches) | 80% | very high |
| September Weather | 18°C (65°F) | 107 mm (4.2 inches) | 75% | very high |
| October Weather | 9°C (48°F) | 79 mm (3.1 inches) | 77% | moderate |
| November Weather | 1°C (35°F) | 25 mm (1.0 inches) | 85% | moderate |
| December Weather | -3°C (26°F) | 39 mm (1.5 inches) | 83% | low |