The weather in Portsmouth in August is very hot. The average temperatures are between 23°C and 30°C, drinking water regularly is advisable.
You can expect about 3 to 8 days of rain in Portsmouth during the month of August. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Portsmouth in August 2025.
If you’re planning to visit Portsmouth in the near future, we highly recommend that you review the 14 day weather forecast for Portsmouth before you arrive.