The Met Office is ending its amber warning for extreme heat this evening, with a slightly cooler high temperature of 25C predicted tomorrow for the city.
Its forecast also states there will be some cloud and lows of 17C.
However, the weather is expected to drastically change on Saturday with a yellow warning for rain in place and highs of 21C.
The rain warning will remain in place on Sunday across most of England and Wales, with lighter rain and highs of 21C predicted in Portsmouth on Monday and Tuesday.
It comes as the temperatures in the city reached highs of 29C this week, with residents urged to stay cool and hydrated.
Temperatures across the country will also plummet at the weekend with ‘heavy rain and thundery showers at times’ and ‘temperatures generally falling towards average’.