Beijing's subway system initiated dual temperature mode on June 1 to improve the travel experience of passengers.
In addition, all 1,041 fans installed at 56 ground stations were turned on to improve temperatures on the platforms.
Wang Yu, director of the subway's publicity department, said temperatures in "cold" cars will be 22 to 24 degrees Celsius and "cool" cars will be kept between 24 and 26 C.
"The weather is very hot, so I recommend cold car," a passenger said.
The dual temperature mode started in 2019.