Last updated: June 24, 2025
In December, the average temperature in St Johnsbury, United States hovers around -5°C (23°F). However, prepare for extremes, as temperatures can plummet to a chilling -31°C (-24°F) or rise to a moderate 14°C (58°F). Expect 85 mm (3.3 in) of precipitation spread across 14 days, contributing to the high average humidity of 85%. Stay warm and dry during this crisp and wet month!
In December in St Johnsbury, the average temperature is -5°C (23°F), with a maximum that can reach 14°C (58°F) and a minimum that can drop as low as -31°C (-24°F). Travelers should be prepared for a significant temperature range, with the potential for very cold days, so packing appropriate winter gear is essential.
In St Johnsbury in December, the precipitation amount is 85 mm (3.3 in) over the course of 14 days.
In St Johnsbury in December, humidity is 85%. With an average temperature of -5°C (23°F), this humidity feels like a biting chill that clings to your skin, making even the briefest outdoor excursions feel daunting and uncomfortable.
In St Johnsbury 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 St Johnsbury, you can visit Hourly UV Index in St Johnsbury.
UV Risk Categories
Weather in St Johnsbury varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in St Johnsbury, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -8°C (18°F) | 80 mm (3.1 inches) | 91% | low |
| February Weather | -6°C (21°F) | 78 mm (3.1 inches) | 89% | moderate |
| March Weather | -2°C (29°F) | 69 mm (2.7 inches) | 85% | moderate |
| April Weather | 5°C (42°F) | 110 mm (4.3 inches) | 84% | very high |
| May Weather | 12°C (55°F) | 95 mm (3.7 inches) | 78% | very high |
| June Weather | 17°C (63°F) | 98 mm (3.9 inches) | 72% | very high |
| July Weather | 20°C (69°F) | 106 mm (4.2 inches) | 75% | very high |
| August Weather | 19°C (67°F) | 88 mm (3.5 inches) | 74% | very high |
| September Weather | 15°C (60°F) | 64 mm (2.5 inches) | 77% | high |
| October Weather | 9°C (48°F) | 138 mm (5.5 inches) | 85% | moderate |
| November Weather | 0°C (33°F) | 103 mm (4.0 inches) | 86% | moderate |
| December Weather | -5°C (23°F) | 85 mm (3.3 inches) | 85% | low |