It was 90 degrees outside on Tuesday afternoon, but inside Boston’s Park Street station, passengers were pacing back and forth in stagnant 102-degree air.

Red Line passengers crowded the platform while waiting for delayed trains. Shelene, a caregiver, takes the T daily. Dressed in a long sleeve blouse and pants, she wiped sweat from her brow and cheeks as she tended to a child in a stroller. “Some days it’s smooth going,” she said, “but the next day, the heat on the train is too much.” Her eyes darted back and forth from the child to the screen that read “BRAINTREE DELAYED 3:40.”

Boston temperatures have hit record highs this summer with heat waves in June and July, combined with high humidity. This stark increase in temperature has led to weather advisories encouraging people to find ways to stay cool — but for those who have to take the MBTA, it seems near impossible.

Underground subway stations absorb heat from sidewalks and buildings above ground, known as “ heat sink.” Additionally the train’s brakes and air conditioning, as well as the sheer amount of people on the platform, all release heat into stations.

While air conditioning on the actual cars provides a sense of relief for passengers once they board, long waits for delayed trains leave commuters searching for other ways to travel. Even after waiting at 100-plus degree stations, riders still find that some trains don’t have functioning air conditioning.

At Park Street, college students Yena and Karina got tired of waiting for the sluggish Green Line and instead pulled out their smartphones to book a ride through Uber.

“During extreme heat conditions, the MBTA makes sure that every available fan on platforms, mounted on ceilings and columns, and in vent shafts are activated and operational,” Maya Bingaman, MBTA communications manager, said via email.

She said the MBTA handed out slushies at Wellington, Forest Hills and Government Center on Tuesday in an effort to cool down riders. Two of those locations — Wellington and Forest Hills — are above-ground stations and do not suffer from the same air circulation issues or heat absorption from the ground as stops like Park Street.

At Downtown Crossing, where it was 96 degrees early Tuesday afternoon, many riders ducked into the Roche Bros. connected to the station to cool off. Sweat from commuters’ backpacks or tote bags stained their shirts as they crowded around sparsely placed fans.

At Boylston, which measured 97 degrees around noon, a Green Line rider hauled several full grocery bags down the platform as perspiration built under her glasses.

“It’s very, very hot,” Molly shouted as she ran to her train. “I’m so sweaty.”

Back at Park Street, first-time rider TJ glanced between the time on his phone and the train times, his eyes widening after realizing the next Riverside train wouldn’t come for another 12 minutes. “I come from Philly,” TJ said, “and in Philly it’s a lot more cooler. There’s air conditioning.” The population of Philadelphia is more than double Boston’s, but the number of public transit riders in each city is similar. In May 2024, Boston had an average of 788,948 weekday riders while Philadelphia had an average of 717,630.

In workplaces that have business dress codes, planning for attire on these blistering commutes has been a challenge.

Michaela takes the Green Line at Park Street to work at the State House every day. “Wearing formal clothes is kind of hard because it’s so hot, and then at the State House it gets kind of cool so I’m constantly changing layers,” she said, “but even above ground is cooler than down here.”

Temperatures in Boston peak from 4 to 8 p.m., when most commuters are traveling from work. Riders GBH News spoke to on Tuesday mentioned the MBTA stations being the worst at these times, as fans fail to cool such masses of people and the air conditioning on the trains malfunction.

Commuters hope for change in the coming weeks — whether it be from the MBTA or from fall weather.