ATHENS.- The suffocating heat in Athens has forced its top attraction, the Acropolis, to close to tourists in the afternoons for the second time this month, with plans to open up in the cooler hours of the evening. But a strike by workers at that site and others, over dangerous working conditions, will likely keep it closed in the afternoons while the extreme temperatures endure.

Greece is suffering through its second heat wave in as many weeks, and temperatures are expected to reach 111 degrees Fahrenheit, or 44 Celsius, in Athens on Sunday. Workers say the heat poses a potential risk to them and to visitors, and they stopped working at noon Thursday and Friday and plan to continue doing so until at least Sunday. Their union says they will reassess the situation Monday.

Speaking to Greek radio Friday morning, the head of the union, Ioannis Mavrikopoulos, said the temperature on the site of the Acropolis, home to the gleaming white marble Parthenon monument and few shade trees, had reached 118 degrees Fahrenheit, or 48 Celsius. The Acropolis is perched on a rocky outcrop high above Athens.

Mavrikopoulos claimed that between 20 and 25 visitors fainted at the site daily, adding that similar problems had been reported at two other popular sites: the ancient palace of Knossos on Crete and ancient Olympia in northern Greece.

The walkout means that the Acropolis will be accessible to tourists for only four hours a day, from its opening at 8 a.m. until noon. The site has had about 21,000 visitors a day this summer, up by more than a third from last year.

Despite the sweltering heat, tourists continued to try to visit the Acropolis, Greece’s ancient citadel, and its magnificent Parthenon monument, known as a model of classical architecture but also for the sculptures that were hacked off the Parthenon in the early 19th century and have since sat in the British Museum.

The site draws millions of people ever year, and this summer they have been waiting under canopies set up on the paths up to the Acropolis as Red Cross volunteers hand out bottles of water to keep them hydrated. The turnout seems to have ebbed slightly compared with early last week when televised footage showed huge crowds shuffling through the site.

Visitors who booked in advance but were unable to gain access to the Acropolis will be able to use their tickets anytime over the next year, a Culture Ministry official said.

Forecasts suggest that Greece will see a small dip in temperatures Monday but that is expected to be followed by a third heat wave two days later. With the heat enduring well after sunset, it is likely that the country’s archaeological sites will continue to restrict afternoon visits.

This article originally appeared in The New York Times.