A citizen map reveals where it gets hottest on the Madrid Metro

The website lets any user report having travelled on a train with inadequate air conditioning. From those reports, the platform generates its own indicator reflecting passengers’ perception and classifies each line by comfort level, from normal situations to cases considered especially problematic.

Its promoters stress that it is not an official thermometer or a scientific temperature measurement. The system is based on citizen participation and combines the number of incidents, their frequency and the age of reports to create a record that can detect patterns over the weeks.

So far, lines 1 and 5 account for a large share of reports published by users. Both are among the network’s most used lines and for years have accumulated complaints related to air-conditioning performance during episodes of intense heat.

The initiative has reopened the debate about comfort on public transport. Neighbourhood associations are calling for renewal of air-conditioning systems to progress faster, while recalling that high temperatures particularly affect older people, children and passengers making long journeys.

For its part, Comunidad de Madrid awarded this year a €3.5 million contract to strengthen maintenance of air conditioning on 93 trains on lines 1 and 5. The work covers 744 air-conditioning units and includes preventative work, fault repair and replacement of components to improve system performance.

While those improvements gradually reach the network, platforms such as Termo de Madrid allow passengers to share their experience and find out which lines record more incidents. The result is a collaborative picture of thermal comfort on the underground that once again places air conditioning among the main concerns of those who use the Metro every day.