Just how hot is it?Oh, that’s simple, just look at the numbers and you’ll know exactly.The Weather Service says 106. One bank sign flashes 111, but the other one shows 107. The weather app on my phone says 105.OK, so it’s hot, but how hot is it really.The weather folks say to get the real “feel,” you need to use a Heat Index.They throw in humidity and other ingredients – something like computing wind chill in reverse – and come up with a new number.But before gauging heat became a math equation, grandma could tell when it got really, really,