Portsmouth Weather in December
December in Portsmouth typically sees daytime highs of 5°C (41°F) and nighttime lows of -4°C (25°F). Rainfall is also possible this month, so it's worth packing an umbrella. It falls within the winter season.
Rainfall in Portsmouth in December
This month experiences about 14 days of snow/rain according to historical data, averaging 128 mm (5 in). The rain this month tends to fall in heavier spells rather than light drizzle. When it rains, showers can be significant.
Temperature in Portsmouth in December
In December, Portsmouth gets low temperatures, with highs of 5°C (41°F). Nights cool to around -4°C (25°F). December is a notable month of the winter season. Expect a distinctly cold feel throughout the day, not just overnight. Nights drop below freezing to -4°C (25°F). An extra blanket is worth packing if you're unsure about the heating where you're staying. This month is marked by cold temperatures, so wearing layers is key to staying warm. Don't be caught off-guard by the cold.
Sunshine in Portsmouth in December
The month experiences a moderate amount of sunlight, with 134 hours of sunshine. This provides a nice balance between sunshine and clouds.If you prefer dry days with pleasant temperatures, December may not be the ideal month to visit Portsmouth. Our weather planner can help you explore destinations with more pleasant weather conditions.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit the United States of America, check out our Portsmouth's climate page.
Portsmouth Temperature in December
Min Temperature
-4°C (25°F)
Max Temperature
5°C (41°F)
Chance of Rain
45%
Precipitation
128 mm (5 in)
Rainy days
14 days
Humidity
72% *
Sunshine
134 hours *
Percentage Sunshine
*
Daily Historical Temperatures
49-year average (1976-2025)
Based on our historical records, temperatures in Portsmouth typically drop from around 5°C (41°F) at the start of December to approximately 2°C (36°F) by the end. Nights are very cold, with lows typically ranging from -8°C (18°F) to -2°C (28°F).
Average temperatures in December
Daily Historical Precipitation
49-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in December
Historical weather for Portsmouth in December
Browse day-by-day weather records for Portsmouth spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Portsmouth historical weather extremes in December
The extremes listed below come from historical weather data collected in Portsmouth from 1997 through 2025.
- The hottest December day on record in Portsmouth reached 18°C (64°F) (December 6, 2011).
- The coldest night in December in Portsmouth was on December 29, 2017, with a minimum of -20°C (-4°F).
- Peak precipitation in December occurred on December 14, 2019, when 68 mm (2.7 in) of precipitation was measured.
Best Places in the United States of America in December
Find out more about the weather in the United States of America and which places have the best travel conditions in this month. See all of the United States of America in December →
perfect weather
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tolerable
unpleasant
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What to Wear in Portsmouth in December
Cold weather calls for smart layering in December. A thermal base layer makes a huge difference in staying warm. Add a wool sweater or fleece, then a wind-resistant outer jacket. Prepare for significant rainfall with proper waterproof clothing and shoes. It won't hurt to bring your sunglasses along, as you'll see some sunny periods.What To Do in Portsmouth in December
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit the United States of America, check out our Portsmouth's climate page.
Temperature Rainfall Sunshine Humidity
See the full Portsmouth climate overview or explore weather in the United States of America.
