Portsmouth Weather in January
January in Portsmouth sees daytime temperatures around 1°C (34°F) and lows of -8°C (18°F) at night. As the driest month of the year.
Rainfall in Portsmouth in January
This is the driest month of the year, though the temperatures are on the cooler side. Past climate data indicates that roughly 12 days will see snow/rain, totalling around 86 mm (3.4 in) for the month. 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 January
If you're visiting Portsmouth in January, expect highs of 1°C (34°F) and overnight lows around -8°C (18°F). Experience the winter season in January. Cold conditions tend to persist from morning through evening, so be prepared for winter weather. At -8°C (18°F) overnight, frost and ice are likely outside. Indoors, consider packing an extra blanket if you're unsure about the heating. Prepare for the coldest month of the year by packing warm and cozy winter cloths.
Sunshine in Portsmouth in January
The month experiences a moderate amount of sunlight, with 162 hours of sunshine. This provides a nice balance between sunshine and clouds.Our weather planner can help you find worldwide destinations with pleasant weather during this period. September typically offers the best weather for Portsmouth.
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 January
Min Temperature
-8°C (18°F)
Max Temperature
1°C (34°F)
Chance of Rain
40%
Precipitation
86 mm (3.4 in)
Rainy days
12 days
Humidity
67% *
Sunshine
162 hours *
Percentage Sunshine
*
Daily Historical Temperatures
51-year average (1976-2026)
Based on our historical records, temperatures in Portsmouth typically stay consistent throughout January, with daily highs averaging around 1°C (34°F). Nights are very cold, with lows typically ranging from -12°C (10°F) to -7°C (19°F).
Average temperatures in January
Daily Historical Precipitation
51-year average (1976-2026)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in January
Historical weather for Portsmouth in January
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 January
Our historical data for Portsmouth spans 1976 to 2025, revealing these weather extremes.
- On January 6, 2007, temperatures climbed to 21°C (70°F), marking the warmest January day on record.
- The wettest day in January Portsmouth was on January 10, 2024 with 50 mm (2 in) of precipitation.
Best Places in the United States of America in January
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 January →
perfect weather
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tolerable
unpleasant
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What to Wear in Portsmouth in January
Dress warmly and in layers for your trip to Portsmouth in January. A good base layer system works wonders. Start with good thermal underwear, add something warm like a fleece sweater, then finish with a waterproof jacket on top. Expect heavy rainfall, so bring good rain protection and waterproof bags. Sunglasses could come in handy during the sunnier parts of your trip.What To Do in Portsmouth in January
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.
