Last updated: June 24, 2025
In December, the average temperature in Greenwich, United States hovers around -1°C (31°F). Expect temperature extremes, with minimums plunging to -27°C (-16°F) and maximums reaching up to 16°C (60°F). During this month, the region experiences an average precipitation of 99 mm (3.9 in) over approximately 12 days, accompanied by an average humidity of 84%.
In December in Greenwich, the average temperature is -1°C (31°F). The maximum can reach 16°C (60°F) and the minimum can be as low as -27°C (-16°F). Travelers should prepare for a wide range of temperatures and pack accordingly to enjoy their stay.
In Greenwich in December, the total precipitation amount is 99 mm (3.9 in) recorded over a span of 12 days.
In Greenwich in December humidity is 84%. With an average temperature of -1°C (31°F), this humidity feels like a biting chill that seeps through layers of clothing, making outdoor excursions brisk and invigorating, yet challenging for those unaccustomed to such damp conditions.
In Greenwich 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 Greenwich, you can visit Hourly UV Index in Greenwich.
UV Risk Categories
Weather in Greenwich varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Greenwich, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -3°C (26°F) | 77 mm (3.0 inches) | 89% | moderate |
| February Weather | -2°C (29°F) | 95 mm (3.8 inches) | 88% | moderate |
| March Weather | 2°C (35°F) | 79 mm (3.1 inches) | 86% | high |
| April Weather | 8°C (47°F) | 121 mm (4.8 inches) | 84% | very high |
| May Weather | 15°C (59°F) | 89 mm (3.5 inches) | 76% | very high |
| June Weather | 20°C (68°F) | 82 mm (3.2 inches) | 72% | very high |
| July Weather | 23°C (73°F) | 108 mm (4.3 inches) | 66% | very high |
| August Weather | 22°C (72°F) | 80 mm (3.2 inches) | 64% | very high |
| September Weather | 18°C (64°F) | 87 mm (3.4 inches) | 72% | high |
| October Weather | 12°C (53°F) | 142 mm (5.6 inches) | 81% | moderate |
| November Weather | 4°C (39°F) | 106 mm (4.2 inches) | 87% | moderate |
| December Weather | -1°C (31°F) | 99 mm (3.9 inches) | 84% | low |