Fashion designers showcase their wares a season in advance, so we already know what everyone is going to be wearing long before they're wearing it. But hairstyles are a trickier prospect: as the heat encroaches and the humidity advances, there is not yet a reliable gauge to intuit how everyone will cope with their coifs. To satisfy our endless fount of curiosity—not to mention our armchair hankering for mathematics—we did a little investigative reportage this week on New York's sticky streets, gathering data and scribbling furiously in our notebooks, and came up with a quite reliable, accurate chart predicting what you and everyone you know will be doing with your headpieces in the coming months.