As New York City enters the second day of dangerously hot weather, more than 40% of its roughly 500 designated cooling centers will be closed Wednesday due to the federal holiday of Juneteenth, according to City Comptroller Brad Lander.

An analysis by the comptroller’s office found that 239 cooling centers — air conditioned indoor facilities that are free to the public — will be closed for the holiday. The vast majority of them are public libraries.

“We need a provision when there’s a heat wave for them to be open,” Lander said. “It doesn’t matter whether your heatwave hits on Sunday or your heatwave hits on Juneteenth, you need the capacity to have your cooling centers open.”

The closures come after days of warnings about the anticipated high temperatures from Mayor Eric Adams, who activated the city’s emergency heat plan on Tuesday when a heat wave was forecast to last until Friday. An estimated 350 New Yorkers die on average each summer due to hot weather.

The use of libraries as cooling centers has been a focal point because of budget cuts that have forced most branches to close on Sundays.

The mayor’s office did not comment on Lander’s criticisms, but emergency management officials sought to ease concerns about the closures.

“We understand concerns regarding the closure of some libraries tomorrow during the holiday,” Aries Dela Cruz, an emergency management spokesperson, said in an emailed statement. “It’s important to emphasize that there are numerous ways to stay cool in New York City, including over 300 cooling centers that are not libraries, and there have been holidays in the past when libraries have not been open.”

In a post on X, Emergency Management Commissioner Zach Iscol described the comptroller’s analysis as a “significant misrepresentation” although he did not refute the numbers.

Iscol noted that the National Weather Service had not issued a heat advisory — when temperatures are forecasted to climb to 95 degrees and higher for at least 2 consecutive days — and that other cities operate far fewer cooling centers.

City officials have begun urging New Yorkers to seek other air-conditioned spaces besides official cooling centers.

“We’re really trying to get New Yorkers to think about what are cool options, cool spaces, a friend’s house, some place with air conditioning they go to,” Iscol said during a press conference at City Hall on Monday.

He suggested coffee shops, restaurants, movie theaters, and museums as alternatives, although cooling centers are traditionally meant to serve those who are most vulnerable and with the fewest resources.

This is not the first that Lander has criticized the city for poor planning during heat waves. In 2022, his office released a report that found that at least half of the city’s cooling centers were closed during a July heatwave that fell over a weekend. At the time, Lander said the city needed to improve its outdated approach as climate change ushers in hotter temperatures.

Lander said the city should be ready to deploy emergency contracts to ensure that cooling centers can stay open no matter what day the heat wave falls on.

“Extreme heat is the most significant cause of death as a result of the climate crisis,” he said. “We need to be ready.”