Portsmouth in Winter
In winter (December, January and February), Portsmouth sees average daytime highs around 36°F and overnight lows near 24°F, with 11.5 in of precipitation over about 30 wet days across the season. It is the coldest season of the year and the 3rd-wettest season.
Over the season highs ease from about 42°F in early December to 37°F by late February. The sky is clear or mostly clear about 33% of the time across winter, and the air most often feels dry.
Winter is Portsmouth's weakest season of the year to visit on our travel score. For the whole year in context, see Portsmouth's year-round climate.
- Avg daytime high
- 36°F
- coldest season of the year
- Avg overnight low
- 24°F
- Precipitation
- 11.5 in
- 30 wet days
- Avg wind
- 11 mph
- Travel score
- 0.0
- weakest season of the year
- Months
- Dec · Jan · Feb
Temperature in Portsmouth in Winter
Over the season highs ease from about 42°F in early December to 37°F by late February.
A typical winter day in Portsmouth reaches about 36°F and drops to 24°F overnight. The warmest of the three months is December, the coolest January.
How winter really feels in Portsmouth
Once humidity and wind are folded in, winter brings about 0 days that feel above 90°F and 90 that feel at or below 32°F.
The story in winter is cold — wind chill drags the overnight "feels like" below the raw low.
Portsmouth weather by month
How the three winter months (December, January and February) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°F) | Rainfall (inches) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 34° / 22° | 3.6 | 9.9 | 6.7 | 9.2 | 0.0 |
| Feb | 35° / 23° | 3.4 | 9.1 | 6 | 10.2 | 0.0 |
| Mar | 41° / 30° | 4.5 | 11.2 | 5.2 | 11.6 | 0.2 |
| Apr | 51° / 40° | 4.2 | 10.6 | 1.3 | 13.1 | 2.4 |
| May | 60° / 49° | 3.3 | 10.5 | 0 | 14.4 | 4.7 |
| Jun | 69° / 58° | 3.6 | 10.6 | 0 | 15.1 | 6.3 |
| Jul | 75° / 65° | 3.1 | 10.6 | 0 | 14.9 | 6.9 |
| Aug | 74° / 64° | 3.2 | 8.8 | 0 | 13.8 | 7.2 |
| Sep | 68° / 57° | 3.4 | 8.5 | 0 | 12.3 | 6.6 |
| Oct | 58° / 47° | 4.4 | 9.9 | 0.2 | 10.8 | 4.5 |
| Nov | 48° / 37° | 3.8 | 9.7 | 1.2 | 9.5 | 1.8 |
| Dec | 39° / 28° | 4.6 | 10.8 | 4.9 | 8.9 | 0.1 |
Cloud cover in Winter
The sky is clear or mostly clear about 33% of the time across winter.
Chance of precipitation in Winter
Portsmouth gets around 11.5 in of rain and snow over 30 wet days across winter. The line is the day-by-day chance of measurable precipitation.
Humidity in Winter
Most of winter feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Winter
Winds average 11 mph across winter.
Sunrise & sunset in Winter
Daylight runs from about 9 h 06 min in early December to 10 h 48 min by late February. The lit band spans sunrise to sunset each day.
Solar energy in Winter
Average shortwave solar energy reaching the ground each day across winter, about 2.1 kWh/m².
Hazard calendar for Portsmouth
None of Portsmouth's seasonal hazards peak in winter. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do.
Portsmouth sits in the Atlantic hurricane belt; the season peaks August–October.
Is winter a good time to visit Portsmouth?
Our two travel scores rate winter for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
winter is a weaker month for outdoor sightseeing in Portsmouth.
What to pack for Portsmouth in Winter
From winter's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In winter, Portsmouth sees daytime highs around 36°F and nights near 24°F. Pack a warm layer and a heavy coat. Worth having: rain gear. About 30 days see rain.
Sea temperature near Portsmouth in Winter
The nearest coast averages about 42°F across winter — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea offshore is warmest in August at about 65°F and coldest in March near 38°F.
The water stays below 68°F all year — cool enough that most swimmers want a wetsuit.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°F) | 42 | 39 | 38 | 42 | 49 | 57 | 63 | 65 | 62 | 55 | 49 | 45 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Cool | Cool | Cool | Bracing | Bracing | Bracing |
| Sea temperature (°F) | Comfort | |
|---|---|---|
| Jan | 42 | Bracing |
| Feb | 39 | Bracing |
| Mar | 38 | Bracing |
| Apr | 42 | Bracing |
| May | 49 | Bracing |
| Jun | 57 | Bracing |
| Jul | 63 | Cool |
| Aug | 65 | Cool |
| Sep | 62 | Cool |
| Oct | 55 | Bracing |
| Nov | 49 | Bracing |
| Dec | 45 | Bracing |
UV index in Portsmouth in Winter
Clear-sky midday UV across winter averages around 2. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Portsmouth peaks around July 10 at about 7 (very high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near December 23 at about 1 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 1 | 2 | 4 | 5 | 7 | 7 | 7 | 4 | 6 | 3 | 2 | 1 |
| Level | Low | Moderate | Moderate | High | High | High | Very high | Moderate | High | Moderate | Moderate | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 1 | Low |
| Feb | 2 | Moderate |
| Mar | 4 | Moderate |
| Apr | 5 | High |
| May | 7 | High |
| Jun | 7 | High |
| Jul | 7 | Very high |
| Aug | 4 | Moderate |
| Sep | 6 | High |
| Oct | 3 | Moderate |
| Nov | 2 | Moderate |
| Dec | 1 | Low |
Where is Portsmouth?
Portsmouth sits at 43.1°N, 70.8°W, 20 ft above sea level, in United States. The nearest listed city is Dover, 9.9 mi away.
Topography around Portsmouth
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Portsmouth.
Within 2 miles, the terrain around Portsmouth has only modest variations in elevation — a maximum elevation change of 161 ft around an average of 39 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 430 ft; within 50 miles, large variations in elevation — a maximum elevation change of 2,454 ft.
The land around Portsmouth is covered by trees (45%), water (22%) and artificial surfaces (21%) within 2 miles, trees (49%) and water (36%) within 10 miles, and trees (61%) and water (32%) within 50 miles.
United States travel facts
- Power plugs
- Type A / B
- 120 V · 60 Hz
- Prices
- ≈ 100% of US
- price level, 2025
- GDP per capita
- $90,027
- 2025
- Happiness
- 6.8 / 10
- World Happiness, 2025
- Safe drinking water
- 98%
- of population, 2024
- Homicide rate
- 5.8
- per 100k, 2023
- Road deaths
- 12.7
- per 100k/yr, 2019
- Income group
- High
- World Bank
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Portsmouth (43.077°, -70.7577°, elevation 20 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.