Sun, sweat and urban heat islands: How hot is your borough?

Charlie Bone is sweating. In a crowded backroom, the junior policy officer is talking over the noise about why the borough he works for, Hammersmith & Fulham, gets so damn hot. 

“Our buildings are designed to entrap heat,” he says, pausing to roll up the sleeves of his blue-striped shirt for some extra ventilation. “See, look how hot I am in here, and it's a relatively new building”. 

“Here” is the Lyric Hammersmith Theatre, situated on the neighbourhood’s bustling high street, and currently playing host to the Hammersmith & Fulham Climate Action Together summit. On my four-minute walk to the theatre from the tube, I’m trying to gauge my temperature levels and determine if it feels hotter than, say, Westminster, where I’ve just come from. I’m conducting this odd — and highly unscientific — exercise for the same reason I’ve pitched up at this event to assail poor Bone. 

Summer has descended upon London and with it, a fresh new spin on the capital’s exceptionalism complex. London, it’s been decided, might register temperatures that seem low compared to many parts of the world, yet are much harder to deal with. A raft of social media posts and articles have asserted that enduring a 28°C summer’s day in London is worse than 40°C in somewhere like Singapore. 

There are a number of reasons for this: from the city's humidity to its Victorian historic to its clay underpinnings. But why, then, are some parts of the city seemingly hotter than others? And what can we do to cool them down?