Originally published on metropolis.co.jp on November 2013

Once autumn officially arrives, some Tokyo commuter trains are heated to sweat-inducing levels. We tracked down aircon policies for the major train lines.

JR: JR has no set guidelines on what date to turn on the heat, so a judgement call is made based on temperature and weather conditions. Cars  are heated to 23 C in winter. In summer the mildly cooled cars are set for 27 C and the rest are at 25 C.

Odakyu: New carriages have automatic settings to heat cars to 20 C. At suburban stations, only three out of four doors in each car are opened to avoid letting the heat out.

Keikyu: Conductors make the decision to turn on the heat, set for 18 C based on the outdoor temperature and how crowded the train is.

Tokyo Metro: The conductor gets to set the thermostat to maintain good air quality in the train based on crowd conditions and the temperature.