The hottest summer day you remember from childhood could be the norm in a few decades; in fact it looks like the heat has already been cranked up. “When scientists talk about global warming causing more heat waves, people often ask if that means that the hottest temperatures will become ‘the new normal,’” said Noah Diffenbaugh, an assistant professor of environmental Earth system science at Stanford, in a press release. “That got us thinking –- at what point can we expect the coolest seasonal temperatures to always be hotter than the historically highest temperatures for that season?”