Why NYC’s Subway Stations Are Hitting 132°F—and What’s Being Done About It

The Underground Furnace: NYC’s Subway Crisis Reaches Breaking Point

If you’ve braved the New York City subway this summer, you know the feeling: stepping underground feels like walking into a sweltering oven. Recent readings have pushed past 100°F on station platforms, with the heat index soaring to a staggering 132°F in some areas. For daily commuters and essential workers alike, the aging transit system is becoming increasingly unbearable.

Jack Klein takes temperature readings on a subway platform in New York City.

A Citizen Scientist Fights the Heat

Enter Jack Klein, a 31-year-old construction site manager who has taken it upon himself to document the city’s subway heat crisis. By magnetizing thermometers to steel beams across seven of Manhattan’s hottest stations, Klein has been tracking the Hades-like temperatures that riders endure daily. His viral social media videos have brought national attention to a problem many locals have long accepted as just another part of living in NYC.

“This line must be cursed,” Klein noted while monitoring a platform at 14th Street-Union Square, where temperatures regularly run 10 degrees hotter than above ground. While older commuters often tell newcomers to “suck it up”—reminding them that full air conditioning wasn’t installed until 1993—Klein views this as a critical public health issue. He’s now distributing large water dispensers to platforms and demanding better seating and functional fans.

The heat index reached 132 F in an elevated section of the Brooklyn Bridge-City Hall and Chambers Street subway complex in Manhattan.

Why the Underground Is Overheating

The root of the problem lies in a perfect storm of climate change and century-old infrastructure. Designed over 100 years ago, NYC’s subway relies on a crude piston ventilation system where incoming trains push hot air out through vents. Unfortunately, this outdated method can’t keep up with modern extreme weather.

Several factors compound the heat:

• Trains dump hot AC exhaust directly back into the tunnels and stations.
• Concrete and steel absorb and trap heat, releasing it slowly throughout the day.
• Crowded platforms add human body heat (each person generates ~100 watts), pushing temperatures up to 20°F higher than street level.

Environmental engineer Giorgia Chinazzo from Northwestern University warns that underground systems are heating up faster than surface environments. “Our built environment isn’t designed for [the current] climate crisis,” she explains. “In older systems like in London and New York, the metro systems just can’t deal with this.”

The Human Toll

While passengers complain and sweat, subway staff—including maintenance workers, cleaners, and operators—face the most severe risks. Labor unions have repeatedly flagged these conditions as dangerous, citing heat exhaustion and heatstroke as real threats for employees forced to work in these stifling environments for hours on end.

A Groundbreaking Geothermal Solution

Recognizing the urgency, city and state officials have unveiled a first-of-its-kind thermal energy network to tackle the sweltering platforms. The innovative plan focuses on the notoriously hot Brooklyn Bridge-City Hall and Chambers Street station complex.

The system works by pumping chilled liquid through pipes behind walls and under flooring to extract heat from the platforms. This warmed liquid is then funneled into storage boreholes drilled up to 600 feet underground. During colder months, that stored thermal energy will be repurposed to warm nearby municipal buildings, including City Hall and two courthouses.

Commuters brace for the heat at one of the city’s most blistering stations.

According to MTA CEO Janno Lieber, the project could drop platform temperatures by several degrees—“the difference between total misery and merely sweltering.” Mayor Zohran Mamdani hailed the initiative as a dual victory for climate resilience and urban infrastructure: “We would be making these stations cool again, and we’d be making what is old new again... lower energy costs, a more resilient subway system and a cleaner energy future.”

While the concept mirrors ancient Roman and Persian cooling techniques, modern NYC applications are already proving successful at landmarks like St. Patrick’s Cathedral and the NYBG. As the MTA expands these pilot programs, New Yorkers may finally see relief from the underground saunas that have defined their summer commutes for too long.