Portsmouth in Summer
In summer (June, July and August), Portsmouth sees average daytime highs around 71°F and overnight lows near 65°F, with 10.2 in of rain over about 27 wet days across the season. It is the warmest season of the year and the driest season of the year.
Over the season highs climb from about 62°F in early June to 72°F by late August. The sky is clear or mostly clear about 34% of the time across summer, and the air most often feels humid.
Summer is Portsmouth's best 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
- 71°F
- warmest season of the year
- Avg overnight low
- 65°F
- Rainfall
- 10.2 in
- 27 wet days
- Avg wind
- 10 mph
- Travel score
- 6.7
- best season of the year
- Months
- Jun · Jul · Aug
Temperature in Portsmouth in Summer
Over the season highs climb from about 62°F in early June to 72°F by late August.
A typical summer day in Portsmouth reaches about 71°F and drops to 65°F overnight. The warmest of the three months is July, the coolest June.
How summer really feels in Portsmouth
Once humidity and wind are folded in, summer brings about 0 days that feel above 90°F and 0 that feel at or below 32°F.
summer sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.
Portsmouth weather by month
How the three summer months (June, July and August) 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 | 38° / 28° | 4.4 | 10.6 | 4.5 | 9.3 | 0.0 |
| Feb | 38° / 29° | 3.8 | 9.6 | 3.9 | 10.3 | 0.0 |
| Mar | 42° / 34° | 5.1 | 10.9 | 3.6 | 11.7 | 0.3 |
| Apr | 49° / 42° | 4.6 | 11.4 | 0.6 | 13.1 | 2.0 |
| May | 57° / 51° | 3.9 | 10.9 | 0 | 14.3 | 4.0 |
| Jun | 66° / 60° | 3.7 | 9.3 | 0 | 15 | 6.1 |
| Jul | 73° / 67° | 3.0 | 8.9 | 0 | 14.7 | 7.0 |
| Aug | 73° / 68° | 3.6 | 8.8 | 0 | 13.7 | 7.1 |
| Sep | 68° / 62° | 4.1 | 8.8 | 0 | 12.3 | 6.6 |
| Oct | 60° / 53° | 5.1 | 10 | 0.1 | 10.9 | 5.0 |
| Nov | 51° / 43° | 4.5 | 9.7 | 0.4 | 9.7 | 2.7 |
| Dec | 44° / 35° | 5.2 | 11.5 | 2.9 | 9 | 0.6 |
Cloud cover in Summer
The sky is clear or mostly clear about 34% of the time across summer.
Chance of precipitation in Summer
Portsmouth gets around 10.2 in of rain over 27 wet days across summer. The line is the day-by-day chance of measurable precipitation.
Humidity in Summer
Most of summer feels humid — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Summer
Winds average 10 mph across summer.
Sunrise & sunset in Summer
Daylight runs from about 14 h 48 min in early June to 13 hours by late August. The lit band spans sunrise to sunset each day.
Solar energy in Summer
Average shortwave solar energy reaching the ground each day across summer, about 5.9 kWh/m².
Hazard calendar for Portsmouth
In summer, Portsmouth overlaps its atlantic hurricane season. The full year is below, with each hazard's peak months called out.
Portsmouth sits in the Atlantic hurricane belt; the season peaks August–October.
Is summer a good time to visit Portsmouth?
Our two travel scores rate summer for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
summer is a reasonable time to visit Portsmouth for sightseeing.
What to pack for Portsmouth in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, Portsmouth sees daytime highs around 71°F and nights near 65°F. Pack sun protection. Worth having: light clothes and rain gear. About 27 days see rain.
Sea temperature near Portsmouth in Summer
The nearest coast averages about 66°F across summer — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 17 mi away) is warmest in August at about 69°F and coldest in February near 39°F.
It's comfortable for a long swim from Jul 26 to Aug 30 — about 1.2 months when the water holds above 68°F.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°F) | 43 | 39 | 40 | 44 | 51 | 60 | 67 | 69 | 67 | 61 | 55 | 49 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Bracing | Cool | Cool | Refreshing | Cool | Cool | Bracing | Bracing |
| Sea temperature (°F) | Comfort | |
|---|---|---|
| Jan | 43 | Bracing |
| Feb | 39 | Bracing |
| Mar | 40 | Bracing |
| Apr | 44 | Bracing |
| May | 51 | Bracing |
| Jun | 60 | Cool |
| Jul | 67 | Cool |
| Aug | 69 | Refreshing |
| Sep | 67 | Cool |
| Oct | 61 | Cool |
| Nov | 55 | Bracing |
| Dec | 49 | Bracing |
UV index in Portsmouth in Summer
Clear-sky midday UV across summer averages around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Portsmouth peaks around June 23 at about 8 (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) | 2 | 3 | 4 | 5 | 7 | 8 | 8 | 5 | 6 | 3 | 2 | 1 |
| Level | Low | Moderate | Moderate | High | Very high | Very high | Very high | High | High | Moderate | Moderate | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 2 | Low |
| Feb | 3 | Moderate |
| Mar | 4 | Moderate |
| Apr | 5 | High |
| May | 7 | Very high |
| Jun | 8 | Very high |
| Jul | 8 | Very high |
| Aug | 5 | High |
| Sep | 6 | High |
| Oct | 3 | Moderate |
| Nov | 2 | Moderate |
| Dec | 1 | Low |
Where is Portsmouth?
Portsmouth sits at 41.6°N, 71.3°W, 141 ft above sea level, in United States. The nearest listed city is Middletown, 4.3 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 292 ft around an average of 66 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 358 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,181 ft.
The land around Portsmouth is covered by water (44%), trees (27%) and grassland (20%) within 2 miles, water (44%) and trees (36%) within 10 miles, and trees (50%) and water (43%) 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 (41.6023°, -71.2503°, elevation 141 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.