The highest day temperature in January 2025 was 40°F. The lowest night temperature was 4°F. The average values for day and night temperatures during January were 28.0°F и 19.1°F respectivly.

The average sea surface temperature in January 2025 for Portsmouth was 40.0°F. The maximum and minimum values were 38.2°F and 42.0°F respectively.

Most of the days in January are gloomy but you can also expect sunny days.

Precipitation total in January for Portsmouth is 1.2 in.

The average wind speed in January is 9.7 mph. It makes January one of the most windy months of the year for Portsmouth.

We are using day length and cloud cover information for each day of the month to calculate averages for this chart. Average sunny hours for Portsmouth in January is 4.7 hours.