Last updated: June 24, 2025
In December, the average temperature in Glastonbury, United States hovers around 1°C (34°F), making it a chilly time of year. Expect temperatures to range from a brisk -19°C (-1°F) at their lowest to a mild 17°C (63°F) at their peak. During this period, precipitation amounts average 123 mm (4.9 in) over approximately 10 days, contributing to an average humidity level of 80%. Dress warmly and be prepared for both rain and shine!
In December in Glastonbury, the average temperature is 1°C (34°F). Maximums can reach 17°C (63°F) and minimums can be as low as -19°C (-1°F). Be prepared for a wide range of temperatures while traveling to Glastonbury, as it can be both chilly and pleasantly warm.
In Glastonbury in December, the total precipitation amount is 123 mm (4.9 in) over the course of 10 days.
In Glastonbury in December, humidity is 80%. With an average temperature of 1°C (34°F), this humidity feels like a damp chill that seeps through your layers, making outdoor activities uncomfortable and potentially discouraging for travelers.
In Glastonbury 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 Glastonbury, you can visit Hourly UV Index in Glastonbury.
UV Risk Categories
Weather in Glastonbury varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Glastonbury, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -1°C (31°F) | 66 mm (2.6 inches) | 84% | moderate |
| February Weather | 1°C (33°F) | 86 mm (3.4 inches) | 82% | moderate |
| March Weather | 4°C (39°F) | 89 mm (3.5 inches) | 81% | high |
| April Weather | 9°C (49°F) | 125 mm (4.9 inches) | 78% | very high |
| May Weather | 15°C (60°F) | 113 mm (4.5 inches) | 69% | very high |
| June Weather | 20°C (69°F) | 85 mm (3.4 inches) | 69% | very high |
| July Weather | 24°C (75°F) | 144 mm (5.7 inches) | 62% | very high |
| August Weather | 23°C (74°F) | 90 mm (3.5 inches) | 65% | very high |
| September Weather | 19°C (67°F) | 98 mm (3.8 inches) | 68% | very high |
| October Weather | 13°C (56°F) | 132 mm (5.2 inches) | 74% | high |
| November Weather | 6°C (43°F) | 91 mm (3.6 inches) | 82% | moderate |
| December Weather | 1°C (34°F) | 123 mm (4.9 inches) | 80% | low |