Last updated: June 24, 2025
In December, the average temperature in West Portsmouth, United States hovers around 4°C (40°F). Expect chilly conditions with minimum temperatures dipping as low as -13°C (9°F) and highs reaching up to 20°C (69°F). Throughout the month, the area experiences 112 mm (4.4 in) of precipitation over approximately 11 days, and the air remains quite damp, with an average humidity of 87%.
In December in West Portsmouth, the average temperature is 4°C (40°F). Maximums can reach 20°C (69°F), while minimums can be as low as -13°C (9°F). Be prepared for a wide range of temperatures if you're planning to travel during this time.
In West Portsmouth in December, the precipitation amount is 112 mm (4.4 in) that occurs over the course of 11 days.
In West Portsmouth in December humidity is 87%. With an average temperature of 4°C (40°F), this humidity feels like an uncomfortable chill that seeps into your bones, making it essential to dress warmly and prepare for damp conditions, which can dampen your spirits while traveling.
In West Portsmouth in December, the maximum UV index is 3, which corresponds to a moderate Exposure Category. The time to burn is approximately 30 minutes. For more details on the hourly UV index in West Portsmouth, you can check the information here.
UV Risk Categories
Weather in West Portsmouth varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in West Portsmouth, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 2°C (35°F) | 85 mm (3.3 inches) | 88% | moderate |
| February Weather | 4°C (39°F) | 124 mm (4.9 inches) | 88% | moderate |
| March Weather | 8°C (47°F) | 106 mm (4.2 inches) | 87% | high |
| April Weather | 13°C (55°F) | 128 mm (5.0 inches) | 85% | very high |
| May Weather | 19°C (66°F) | 128 mm (5.0 inches) | 81% | very high |
| June Weather | 23°C (73°F) | 157 mm (6.2 inches) | 82% | very high |
| July Weather | 25°C (78°F) | 107 mm (4.2 inches) | 81% | very high |
| August Weather | 24°C (75°F) | 120 mm (4.7 inches) | 73% | very high |
| September Weather | 21°C (71°F) | 109 mm (4.3 inches) | 73% | very high |
| October Weather | 15°C (60°F) | 116 mm (4.5 inches) | 78% | high |
| November Weather | 7°C (45°F) | 77 mm (3.0 inches) | 89% | moderate |
| December Weather | 4°C (40°F) | 112 mm (4.4 inches) | 87% | moderate |