This map shows which tube lines will be the hottest this summer

Summer’s here and the time is right for stiflingly hot commutes. We’re all familiar with the way the tube becomes a deep-level sauna in the warmer months. But which line is the hottest of all?

Thanks to a canny FOI request by the Gizmodo website, we’ve finally got an official answer from TfL. It’s the baking hot Bakerloo, with an average temperature of 27C in 2016, and a maximum in August of 31C. (Bring on those air-conditioned trains.) Our map shows the other lines you might want to avoid this summer if you don’t want to arrive at work looking like you’ve cycled Mont Ventoux.

Meanwhile, TfL has launched a robot to tell you when your bus is coming.