Greece Closes Schools and Acropolis as Possible Record Heat Is Forecast

Intense heat in Greece prompted a mini lockdown for two days starting on Wednesday, with some schools closing and the Acropolis restricting visiting hours, as the authorities searched for two foreign hikers just a few days after a British medical journalist was found dead on the island of Symi after going for a walk in searing heat.

The onset of sweltering temperatures, which meteorologists said might set a record on Thursday, prompted the Health Ministry to issue a warning to older people and people with chronic ailments to stay indoors. The authorities also advised anyone who works outdoors to avoid strenuous activity from noon to 5 p.m.

Temperatures were forecast to reach 41 Celsius, or 105.8 Fahrenheit, in Athens on Wednesday and rise to 42 Celsius (107.6 Fahrenheit) on Thursday before dipping on Friday, according to Greece’s National Meteorological Service. The heat elsewhere in the Greek mainland was expected to reach 43 Celsius.

The tinderbox conditions also raised concerns about wildfires after a disastrous summer last year, when wildfires killed more than 20 people in Greece and razed vast areas of forestland. Greece’s civil protection authority and the army were conducting 24-hour patrols of major forests this week in an effort to prevent fires from breaking out.

In central Athens on Wednesday, members of the Hellenic Red Cross were distributing bottles of water and sunscreen to homeless people, and the city authorities were operating several air-conditioned venues for people to cool off in.

The Health Ministry also published notices with advice to the public on how to treat people experiencing heat stroke, including transferring them into cool areas and placing ice packs on the neck and armpits.

The searing temperatures spurred the authorities to shut primary schools in many parts of the country on Wednesday, and the Acropolis — Greece’s most visited archaeological site — was closed from noon to 5 p.m. Those restricted hours were announced after a young tourist fainted while waiting in line to see the monument on Tuesday as temperatures rose.

The Culture Ministry imposed similar restrictions on the site last year in an effort to protect workers and tourists, though not until July.

As the temperatures rise, the acute heat has fueled concerns about the fate of two foreign nationals who have gone missing on two Greek islands in recent days. A 74-year-old Dutch tourist was last seen on Sunday morning when he set out for a hike on Samos, and the authorities are searching for a 59-year-old dual citizen of the United States and France who has been missing on Amorgos since Tuesday morning.

On Sunday, the remains of Michael Mosley, a 67-year-old British television presenter, were found on the Greek island of Symi four days after he went missing while out for a walk. An initial post-mortem examination ruled out foul play and appeared to point to death from natural causes, according to a police spokeswoman, who that said results to toxicological tests were pending.

“Hikers go missing every year, and we usually find them safe and well,” said Constantina Dimoglidou, the police spokeswoman. “I don’t know what’s going on this year.”

Ms. Dimoglidou said the extreme heat had also complicated the search efforts. During the search for Mr. Mosley, she said, the police sniffer dog had to be removed from the sun every hour to cool off and protect its paws from burns.

Concern was particularly high on Wednesday for the 74-year-old man on Samos. Ms. Dimoglidou said that the Dutch tourist’s cellphone was switched off.

Dimitris Kalaitzis, a member of the local chapter of the Hellenic Rescue Team, said the man’s wife had relayed that he had only a small bottle of water with him when setting out for his walk. The route the 74-year-old is believed to have taken in southwestern Samos was “arduous,” Mr. Kalaitzis said.