Portsmouth weather in August
Temperature, sea and sunshine in August: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in August
Excellent
Best time to visit: May – September
What is the weather like in Portsmouth in August?
In August, Portsmouth is mild: daytime highs average 21 °C, and nights cool down to about 14 °C. The sea averages 18.0 °C – bracing, so a wetsuit helps for longer swims. The sun shines for around 7 hours a day. Rain is frequent, with about 10 rainy days and 57 mm in total. All in all, August is an excellent month for a holiday in Portsmouth.
August compared
How the weather changes from July to September. Tap a month to open it.
| JulyJul | AugustAug | SeptemberSep | |
|---|---|---|---|
| Score | 83 | 80 | 78 |
| Day | 21° | 21° | 19° |
| Night | 14° | 14° | 12° |
| Sea | 17° | 18° | 18° |
| Sun | 8 h | 7 h | 6 h |
| Rain days | 10 | 10 | 9 |
More details for August
- Daylight
- 14 h 37 min05:51 – 20:28
- UV index
- 6 · highclear sky, noon (estimate)All months
- Muggy days
- 0 daysdew point 18 °C or moreAll months
- Wind
- 22 km/haverage daily peakAll months
- Cloud cover
- 62 %on averageAll months
- Hot days
- 0 days30 °C or more
- Time zone
- UTC+1Europe/London
How the score comes together
- Temperatureweight 50 %100 %
- Sunshineweight 20 %65 %
- Few rainy daysweight 30 %56 %
Each factor is rated from 0 to 100 % and weighted for the travel style “City break”.
What to pack in August
- Wetsuit for longer swims
- Sunscreen
- A jumper for the evenings
- Rain jacket or umbrella
Portsmouth in August: quick answers
Is Portsmouth hot in August?
No. In August, Portsmouth is mild: daytime highs average 21 °C and nights drop to about 14 °C.
Can you swim in Portsmouth in August?
Only if you don't mind cold water: in August the sea averages just 18.0 °C. Comfortable swimming temperatures are not reached at any time of year.
Does it rain much in Portsmouth in August?
Rain is frequent, with about 10 rainy days and 57 mm in total.
Portsmouth month by month
The whole year in PortsmouthAll destinations: United KingdomWhere to go in AugustSea temperature in August
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences