Last updated: June 24, 2025
In Hillsboro, United States, the average temperature in December hovers around -8°C (18°F). However, temperatures can drop as low as -32°C (-26°F) and rise to a maximum of 10°C (49°F). Expect around 39 mm (1.6 in) of precipitation spread over 7 days, and brace for high humidity levels averaging 86%.
In December in Hillsboro, the average temperature is -8°C (18°F), with maximums reaching 10°C (49°F) and minimums dropping as low as -32°C (-26°F). Travelers should be prepared for a wide range of temperatures, ensuring they have warm clothing and gear for the coldest conditions.
In Hillsboro in December, the precipitation amount is 39 mm (1.6 in) over the course of 7 days.
In Hillsboro in December, humidity is 86%. With an average temperature of -8°C (18°F), this humidity feels like a biting chill that seeps into your bones, making travel uncomfortable and frigid, as the damp air accentuates the cold, creating a sharp contrast that can be quite challenging for outdoor activities.
In Hillsboro 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 Hillsboro, you can visit Hourly UV Index in Hillsboro.
UV Risk Categories
Weather in Hillsboro varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Hillsboro, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -12°C (10°F) | 18 mm (0.7 inches) | 90% | low |
| February Weather | -13°C (9°F) | 20 mm (0.8 inches) | 92% | moderate |
| March Weather | -3°C (27°F) | 26 mm (1.0 inches) | 85% | moderate |
| April Weather | 4°C (40°F) | 43 mm (1.7 inches) | 81% | high |
| May Weather | 13°C (57°F) | 54 mm (2.1 inches) | 75% | very high |
| June Weather | 21°C (69°F) | 90 mm (3.5 inches) | 79% | very high |
| July Weather | 22°C (73°F) | 60 mm (2.4 inches) | 76% | very high |
| August Weather | 20°C (69°F) | 85 mm (3.4 inches) | 78% | very high |
| September Weather | 16°C (60°F) | 72 mm (2.8 inches) | 77% | high |
| October Weather | 7°C (44°F) | 80 mm (3.2 inches) | 79% | moderate |
| November Weather | -2°C (28°F) | 23 mm (0.9 inches) | 86% | moderate |
| December Weather | -8°C (18°F) | 39 mm (1.6 inches) | 86% | low |