For those of us who spend much of the year under a grey sky (cough, MR PORTER HQ in London, cough), summer is the most welcome time of year – an excuse to drink more, wear less and enjoy the weather. Until it comes for our hair, that is. When confronted with sweat, heat and humidity, even the most carefully coiffed barnet can devolve into a floppy, greasy mess that can have you looking like a hairy mammoth in a heatwave and a buzzcut starts to sound appealing. But before you reach for the clippers, consider these five summer-proof hair products to help you keep your cool.