See: https://www.wired.co.uk/article/central-line-temperature-london-weather-heatwave https://www.wired.co.uk/article/central-line-temperature-lon... By far th

See: https://www.wired.co.uk/article/central-line-temperature-london-weather-heatwave https://www.wired.co.uk/article/central-line-temperature-lon... By far the most articulate article I have read (so far) on the matter. As the other posters correctly state, it all boils down to the clay retaining heat, the tiny tunnels, and the age of the system. It’s a fascinating problem!