Last updated: June 24, 2025
In December, the average temperature in Lewiston, United States hovers around 1°C (35°F). Expect chilly conditions, with temperatures dipping as low as -16°C (4°F) and soaring to a mild 15°C (60°F). Be prepared for some wet weather, as 90 mm (3.5 in) of precipitation is likely across 15 days. Don't forget your layers; the average humidity reaches a damp 87%, making it feel even cooler!
In December in Lewiston, the average temperature is 1°C (35°F). The maximum can reach 15°C (60°F), and the minimum can be as low as -16°C (4°F). Be prepared for a wide range of temperatures and pack accordingly for your travels.
In Lewiston in December, the total precipitation amount is 90 mm (3.5 in), which occurs over a span of 15 days.
In Lewiston in December humidity is 87%. With an average temperature of 1°C (35°F), this humidity feels like a chilling dampness that seeps into your bones, making travel feel particularly uncomfortable as the cold air clings to your skin and makes each step feel heavier.
In Lewiston 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 Lewiston, you can visit Hourly UV Index in Lewiston.
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 | -2°C (29°F) | 78 mm (3.1 inches) | 91% | low |
| February Weather | -1°C (30°F) | 87 mm (3.4 inches) | 91% | moderate |
| March Weather | 2°C (35°F) | 71 mm (2.8 inches) | 88% | moderate |
| April Weather | 6°C (43°F) | 118 mm (4.6 inches) | 88% | very high |
| May Weather | 11°C (53°F) | 99 mm (3.9 inches) | 82% | very high |
| June Weather | 18°C (64°F) | 81 mm (3.2 inches) | 79% | very high |
| July Weather | 23°C (73°F) | 115 mm (4.5 inches) | 77% | very high |
| August Weather | 22°C (73°F) | 85 mm (3.3 inches) | 72% | very high |
| September Weather | 19°C (66°F) | 73 mm (2.9 inches) | 76% | high |
| October Weather | 13°C (56°F) | 128 mm (5.0 inches) | 83% | moderate |
| November Weather | 6°C (42°F) | 89 mm (3.5 inches) | 88% | moderate |
| December Weather | 1°C (35°F) | 90 mm (3.5 inches) | 87% | low |