Portsmouth Weather in August
With daytime temperatures of 26°C (79°F) and nighttime lows of 16°C (61°F), August in Portsmouth brings high temperatures during the day. Do keep in mind that quite a bit of rainfall is typical. Around 102 mm (4 in) falls on average.
Rainfall in Portsmouth in August
Expect around 10 days of rain based on historical data, with 102 mm (4 in) average. When showers do arrive, they tend to be on the heavier side. Worth being prepared even if rain days are not that numerous.
Temperature in Portsmouth in August
August in Portsmouth sees highs of 26°C (79°F) and lows of 16°C (61°F) overnight. During August, you'll experience the summer season. Overall, the month follows a fairly predictable daily temperature pattern. At 16°C (61°F) overnight, it can feel quite a bit cooler after dark. Worth packing something warmer for evenings, but the cooler temperatures are ideal for sleeping.
Sunshine in Portsmouth in August
Enjoy a sunny month with about 261 hours of sunshine, the clear skies make Portsmouth even more beautiful.Should you favor a climate that's both dry and comfortably warm, September typically offers the most agreeable circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.
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 August
Min Temperature
16°C (61°F)
Max Temperature
26°C (79°F)
Chance of Rain
33%
Precipitation
102 mm (4 in)
Rainy days
10 days
Humidity
74% *
Sunshine
261 hours *
Percentage Sunshine
*
Daily Historical Temperatures
49-year average (1976-2025)
Based on our historical records, temperatures in Portsmouth typically stay consistent throughout August, with daily highs averaging around 26°C (79°F). Nights are pleasant, with lows typically ranging from 14°C (57°F) to 18°C (64°F).
Average temperatures in August
Daily Historical Precipitation
49-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in August
Historical weather for Portsmouth in August
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 August
According to our 28 years of weather records for Portsmouth, the following extremes were recorded between 1997 and 2025.
- The hottest August day on record in Portsmouth reached 37°C (99°F) (August 14, 2002).
- The coldest August day was on August 29, 2009, with a maximum of 16°C (61°F).
- The lowest overnight temperature recorded in August was 6°C (43°F) (August 28, 2025).
- Peak precipitation in August occurred on August 20, 2006, when 61 mm (2.4 in) of precipitation was measured.
Best Places in the United States of America in August
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 August →
perfect weather
pleasant
tolerable
unpleasant
poor
What to Wear in Portsmouth in August
Warm temperatures in August make for comfortable sightseeing weather. Pack breathable fabrics like cotton shirts, knee-length shorts or skirts, and comfortable walking shoes. A thin long sleeve for indoor spaces is handy. Prepare for significant rainfall with proper waterproof clothing and shoes. And with plenty of sunshine hours, don’t forget sunglasses, sunscreen, and maybe a sun hat.What To Do in Portsmouth in August
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.
