Last updated: June 24, 2025
In Watertown, United States, the average temperature in December hovers around -2°C (30°F), with potential extremes ranging from a chilly -22°C (-8°F) to a pleasant 18°C (65°F). During this month, you can expect around 45 mm (1.8 in) of precipitation spread over 6 days. The air is quite humid, with an average humidity level of 81%.
In December in Watertown, the average temperature is -2°C (30°F), with maximums reaching 18°C (65°F) and minimums dropping as low as -22°C (-8°F). Travelers should be prepared for a wide range of temperatures, from cold to mild, making it essential to pack layered clothing.
In Watertown in December, the precipitation amount is 45 mm (1.8 in) over the course of 6 days.
In Watertown in December humidity is 81%. With an average temperature of -2°C (30°F), this humidity feels like a biting chill that makes outdoor activities challenging, as the damp air seeps into your clothing, making you feel colder than the thermometer suggests.
In Watertown 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 Watertown, you can visit Hourly UV Index in Watertown.
UV Risk Categories
Weather in Watertown varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Watertown, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -6°C (22°F) | 51 mm (2.0 inches) | 85% | moderate |
| February Weather | -5°C (23°F) | 49 mm (1.9 inches) | 85% | moderate |
| March Weather | 2°C (36°F) | 57 mm (2.3 inches) | 85% | moderate |
| April Weather | 7°C (46°F) | 103 mm (4.1 inches) | 85% | very high |
| May Weather | 15°C (59°F) | 121 mm (4.8 inches) | 78% | very high |
| June Weather | 21°C (70°F) | 113 mm (4.5 inches) | 80% | very high |
| July Weather | 23°C (74°F) | 102 mm (4.0 inches) | 78% | very high |
| August Weather | 22°C (71°F) | 94 mm (3.7 inches) | 76% | very high |
| September Weather | 18°C (65°F) | 99 mm (3.9 inches) | 79% | very high |
| October Weather | 11°C (51°F) | 114 mm (4.5 inches) | 83% | moderate |
| November Weather | 2°C (37°F) | 43 mm (1.7 inches) | 88% | moderate |
| December Weather | -2°C (30°F) | 45 mm (1.8 inches) | 81% | low |