Last updated: June 24, 2025
In December, the average temperature in Portsmouth, United States hovers around 4°C (39°F), with a minimum dip to -13°C (9°F) and a maximum rise to 16°C (61°F). Expect about 147 mm (5.8 in) of precipitation spread across 11 days, accompanied by an average humidity of 80%. Stay prepared for a chilly and wet experience!
In December in Portsmouth, the average temperature is 4°C (39°F), with maxima reaching up to 16°C (61°F) and minima dropping as low as -13°C (9°F). It’s essential to pack warm clothing to stay comfortable during your travels.
In Portsmouth in December, the total precipitation amount is 147 mm (5.8 in), occurring over the course of 11 days.
In Portsmouth in December, humidity is 80%. With an average temperature of 4°C (39°F), this humidity feels like a damp chill that seeps into your bones, making travel uncomfortable and requiring extra layers to stay warm while navigating through the misty streets.
In Portsmouth 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 Portsmouth, you can visit Hourly UV Index in Portsmouth.
UV Risk Categories
Weather in Portsmouth varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Portsmouth, focusing on differences in temperature, rainfall, humidity, and UV levels.
Temperature | Precipitation | Humidity | UV | |
---|---|---|---|---|
January Weather | 1°C (35°F) | 95 mm (3.8 inches) | 84% | moderate |
February Weather | 2°C (36°F) | 121 mm (4.8 inches) | 84% | moderate |
March Weather | 3°C (39°F) | 119 mm (4.7 inches) | 82% | high |
April Weather | 8°C (46°F) | 147 mm (5.8 inches) | 79% | very high |
May Weather | 12°C (55°F) | 132 mm (5.2 inches) | 75% | very high |
June Weather | 18°C (64°F) | 104 mm (4.1 inches) | 78% | very high |
July Weather | 22°C (72°F) | 104 mm (4.1 inches) | 76% | very high |
August Weather | 22°C (73°F) | 89 mm (3.5 inches) | 76% | very high |
September Weather | 20°C (67°F) | 110 mm (4.3 inches) | 75% | very high |
October Weather | 15°C (60°F) | 169 mm (6.7 inches) | 75% | high |
November Weather | 9°C (48°F) | 117 mm (4.6 inches) | 80% | moderate |
December Weather | 4°C (39°F) | 147 mm (5.8 inches) | 80% | low |