Scorching temperatures across Europe forced the closure of the Acropolis in Athens for a second day as officials warned of even hotter weather next week – when the mercury is forecast to top 40C in several popular Mediterranean tourist destinations.

In cities, those venturing out at all doused themselves in fountains while others sought out pools, the sea or shade in hopes of relief from the heat wave caused by Cerberus.

The high-pressure anticyclone coming from the south was named after the three-headed dog in ancient Greek mythology who guarded the gates to the underworld.

Fifteen cities in Italy, most of them in the country’s centre and south, were under heat advisories signalling a high level of risk for older adults, the infirm, infants and other vulnerable people.

Temperatures remained in the mid-30s Celcius across much of the Italian peninsula on Saturday but were expected to reach between 38C and 40C in Sardinia, Sicily and Puglia.

The cities under alerts included the high-tourism destinations of Bologna, Florence and Rome.

The capital hit a high of 35C on Saturday and was expected to see temperatures as high as 42C on Tuesday.

In Greece’s capital, where the temperature was forecast to reach 41C, officials decided to keep the sun-baked Acropolis monument closed from 12-5.30pm as they did on Friday.

Temperatures were milder in Spain’s Canary Islands but a wildfire on the island of La Palma caused a preventive evacuation of some 500 people.

Officials said shifting winds and the area’s rain-parched dry terrain could increase the number of evacuees.

In Turkey, coastal cities in the south and southwest reached the high 30s and low 40s. The tourism hot spot of Antalya saw a high of 44C.

In the northwestern cities of Edirne, Kırklareli and Tekirdag, 48 people were taken to A&Es with symptoms of heat stroke in the past two days, the state-run Anadolu Agency reported.

The heatwave is also taking its toll on water levels in Istanbul, Turkey’s largest city.

The main water supply at the Omerli Dam reservoir, already at 41% capacity due to low rainfall, was losing 15,422 tonnes of water an hour during the early afternoon, Levent Kurnaz of Bosphorus University’s Centre for Climate Change and Policy Studies told local media.

European countries farther north also sweltered on Saturday.

Authorities in Poland warned older adults in particular to stay indoors or in the shade and well-hydrated as temperatures reached 35C.

In Warsaw city centre, and in other cities, makeshift hose fountains were arranged to let people and their pets cool off.

Police issued warnings about not leaving children or pets unattended inside cars.

To cool off their four-legged friends, some Italian dog owners took their pets to a beach near Rome especially equipped for canines.

Known as Baubeach, or Woofbeach in English, the area can welcome up to 150 dogs per day. They are allowed to roam on the beach off the lead.

“The sea breeze, as you can feel, is something very pleasant that oxygenates and also gives this feeling of almost natural nebulisation. There, this is pleasant for both people and dogs,” Baubeach owner Patrizia Daffina said.

Carlo Cerese took his dog there on Friday.

“Here he is very active all day,” he said.

“Actually when he gets home he takes a good nap. I think that here at least he doesn’t suffer from the heat.”