Last updated: June 24, 2025
In Holliston, United States, the average temperature in December hovers around 1°C (34°F). However, be prepared for extremes, as temperatures can drop to a chilly -23°C (-9°F) or rise to a mild 17°C (63°F). Expect 118 mm (4.6 in) of precipitation spread over about 10 days, contributing to an average humidity level of 81%.
In December in Holliston, the average temperature is 1°C (34°F), with a maximum reaching 17°C (63°F) and a minimum dropping as low as -23°C (-9°F). Be sure to pack warm layers and be prepared for temperature fluctuations if you plan to travel during this time.
In Holliston in December, the total precipitation amount is 118 mm (4.6 in) over a span of 10 days.
In Holliston in December humidity is 81%. With an average temperature of 1°C (34°F), this humidity feels like a damp chill wrapping around you, making traveling uncomfortable as every breath feels heavy and the cold penetration intensifies with the moisture in the air.
In Holliston 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 Holliston, you can visit Hourly UV Index in Holliston.
UV Risk Categories
Weather in Holliston varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Holliston, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -1°C (31°F) | 67 mm (2.6 inches) | 86% | moderate |
| February Weather | 0°C (33°F) | 85 mm (3.3 inches) | 84% | moderate |
| March Weather | 3°C (38°F) | 91 mm (3.6 inches) | 82% | high |
| April Weather | 9°C (49°F) | 124 mm (4.9 inches) | 80% | very high |
| May Weather | 15°C (59°F) | 92 mm (3.6 inches) | 72% | very high |
| June Weather | 20°C (69°F) | 87 mm (3.4 inches) | 72% | very high |
| July Weather | 23°C (74°F) | 131 mm (5.1 inches) | 67% | very high |
| August Weather | 23°C (74°F) | 89 mm (3.5 inches) | 66% | very high |
| September Weather | 19°C (66°F) | 83 mm (3.3 inches) | 71% | high |
| October Weather | 13°C (56°F) | 139 mm (5.5 inches) | 78% | high |
| November Weather | 6°C (43°F) | 96 mm (3.8 inches) | 84% | moderate |
| December Weather | 1°C (34°F) | 118 mm (4.6 inches) | 81% | low |