Portsmouth in Summer
In summer (June, July and August), Portsmouth sees average daytime highs around 85°F and overnight lows near 71°F, with 13.9 in of rain over about 40 wet days across the season. It is the warmest season of the year and the wettest season of the year.
Across summer, daytime highs hold fairly steady around 85°F. The sky is clear or mostly clear about 30% of the time across summer, and the air most often feels oppressive.
Summer is Portsmouth's 3rd-best season to visit on our travel score. For the whole year in context, see Portsmouth's year-round climate.
- Avg daytime high
- 85°F
- warmest season of the year
- Avg overnight low
- 71°F
- Rainfall
- 13.9 in
- 40 wet days
- Avg wind
- 7 mph
- Travel score
- 5.0
- 3rd-best season
- Months
- Jun · Jul · Aug
Temperature in Portsmouth in Summer
Across summer, daytime highs hold fairly steady around 85°F.
A typical summer day in Portsmouth reaches about 85°F and drops to 71°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 42 days that feel above 90°F and 0 that feel at or below 32°F.
The story in summer is heat — humidity pushes the afternoon "feels like" well above the raw temperature.
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 | 49° / 34° | 3.4 | 9.1 | 1.3 | 9.8 | 2.2 |
| Feb | 52° / 35° | 3.0 | 9 | 1.1 | 10.6 | 2.8 |
| Mar | 59° / 42° | 3.9 | 10.4 | 0.5 | 11.7 | 4.5 |
| Apr | 68° / 51° | 3.3 | 9.7 | 0 | 12.9 | 6.4 |
| May | 75° / 59° | 3.7 | 10.9 | 0 | 13.9 | 6.7 |
| Jun | 83° / 68° | 4.1 | 11.7 | 0 | 14.5 | 5.6 |
| Jul | 87° / 73° | 5.2 | 15.1 | 0 | 14.3 | 4.3 |
| Aug | 85° / 71° | 4.7 | 12.9 | 0 | 13.4 | 5.0 |
| Sep | 80° / 66° | 4.7 | 11.1 | 0 | 12.2 | 6.4 |
| Oct | 71° / 55° | 3.7 | 7.9 | 0 | 11 | 7.0 |
| Nov | 61° / 45° | 3.4 | 8.5 | 0.1 | 10 | 5.3 |
| Dec | 53° / 38° | 3.5 | 9.3 | 0.5 | 9.5 | 3.2 |
Cloud cover in Summer
The sky is clear or mostly clear about 30% of the time across summer.
Chance of precipitation in Summer
Portsmouth gets around 13.9 in of rain over 40 wet days across summer. The line is the day-by-day chance of measurable precipitation.
Humidity in Summer
Most of summer feels oppressive — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Summer
Winds average 7 mph across summer.
Sunrise & sunset in Summer
Daylight runs from about 14 h 18 min in early June to 12 h 54 min 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 6.1 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. The water and warmth also suit a beach or pool day.
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 85°F and nights near 71°F. Pack light clothes, rain gear and sun protection. About 40 days see rain.
Sea temperature near Portsmouth in Summer
The nearest coast averages about 76°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 22 mi away) is warmest in August at about 79°F and coldest in February near 41°F.
It's comfortable for a long swim from Jun 3 to Oct 14 — about 4.4 months when the water holds above 68°F.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°F) | 44 | 41 | 45 | 54 | 63 | 72 | 78 | 79 | 76 | 68 | 57 | 49 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Cool | Refreshing | Warm | Warm | Warm | Cool | Bracing | Bracing |
| Sea temperature (°F) | Comfort | |
|---|---|---|
| Jan | 44 | Bracing |
| Feb | 41 | Bracing |
| Mar | 45 | Bracing |
| Apr | 54 | Bracing |
| May | 63 | Cool |
| Jun | 72 | Refreshing |
| Jul | 78 | Warm |
| Aug | 79 | Warm |
| Sep | 76 | Warm |
| Oct | 68 | Cool |
| Nov | 57 | Bracing |
| Dec | 49 | Bracing |
UV index in Portsmouth in Summer
Clear-sky midday UV across summer averages around 8 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Portsmouth peaks around July 12 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 2 (moderate).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 3 | 4 | 5 | 7 | 8 | 9 | 9 | 7 | 7 | 4 | 3 | 2 |
| Level | Moderate | Moderate | High | High | Very high | Very high | Very high | Very high | High | Moderate | Moderate | Moderate |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 3 | Moderate |
| Feb | 4 | Moderate |
| Mar | 5 | High |
| Apr | 7 | High |
| May | 8 | Very high |
| Jun | 9 | Very high |
| Jul | 9 | Very high |
| Aug | 7 | Very high |
| Sep | 7 | High |
| Oct | 4 | Moderate |
| Nov | 3 | Moderate |
| Dec | 2 | Moderate |
Air quality in Portsmouth in Summer
Average fine-particle pollution (PM2.5) through the year — so you can see where summer falls, not just the annual average.
Air quality in Portsmouth is worst in July — around 16 µg/m³ PM2.5 (moderate), about 2.4× the cleanest month (November, 7 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 8 | 9 | 11 | 12 | 13 | 16 | 16 | 14 | 11 | 7 | 7 | 7 |
| Level | Good | Good | Good | Good | Moderate | Moderate | Moderate | Moderate | Good | Good | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 8 | Good |
| Feb | 9 | Good |
| Mar | 11 | Good |
| Apr | 12 | Good |
| May | 13 | Moderate |
| Jun | 16 | Moderate |
| Jul | 16 | Moderate |
| Aug | 14 | Moderate |
| Sep | 11 | Good |
| Oct | 7 | Good |
| Nov | 7 | Good |
| Dec | 7 | Good |
Where is Portsmouth?
Portsmouth sits at 36.8°N, 76.3°W, 10 ft above sea level, in United States. The nearest listed city is Norfolk, 1.2 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 72 ft around an average of 10 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 194 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 230 ft.
The land around Portsmouth is covered by artificial surfaces (52%) within 2 miles, trees (44%), artificial surfaces (22%) and water (20%) within 10 miles, and trees (42%) and water (38%) 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 (36.8354°, -76.2983°, elevation 10 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.