Last updated: June 24, 2025
In December, the average temperature in Lewiston, United States hovers around -5°C (23°F). Expect chilly conditions, with minimum temperatures dipping as low as -19°C (-2°F) and highs reaching up to 10°C (50°F). Additionally, anticipate around 59 mm (2.3 in) of precipitation spread over approximately 11 days, contributing to a notably high average humidity of 88%. Stay warm and prepared!
In December in Lewiston, the average temperature is -5°C (23°F). The maximum can reach 10°C (50°F), while the minimum can drop as low as -19°C (-2°F). It's essential to pack warm clothing and be prepared for a range of temperatures when traveling during this time.
In Lewiston in December, the precipitation amount is 59 mm (2.3 in) over the course of 11 days.
In Lewiston in December humidity is 88%. With an average temperature of -5°C (23°F), this humidity feels like an icy blanket enveloping you, making travel uncomfortable as the cold damp air seeps through layers of clothing, chilling you to the bone.
In Lewiston 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 Lewiston, you can check the information here.
UV Risk Categories
Weather in Lewiston varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Lewiston, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -5°C (23°F) | 68 mm (2.7 inches) | 91% | moderate |
| February Weather | -4°C (25°F) | 89 mm (3.5 inches) | 92% | moderate |
| March Weather | 1°C (34°F) | 63 mm (2.5 inches) | 84% | very high |
| April Weather | 4°C (40°F) | 78 mm (3.1 inches) | 74% | very high |
| May Weather | 9°C (49°F) | 66 mm (2.6 inches) | 62% | extreme |
| June Weather | 17°C (62°F) | 31 mm (1.2 inches) | 56% | extreme |
| July Weather | 22°C (71°F) | 17 mm (0.7 inches) | 44% | extreme |
| August Weather | 20°C (69°F) | 23 mm (0.9 inches) | 37% | extreme |
| September Weather | 15°C (59°F) | 36 mm (1.4 inches) | 46% | very high |
| October Weather | 6°C (43°F) | 49 mm (1.9 inches) | 67% | high |
| November Weather | 0°C (33°F) | 56 mm (2.2 inches) | 84% | moderate |
| December Weather | -5°C (23°F) | 59 mm (2.3 inches) | 88% | moderate |