Sometimes at Grist HQ, we ask ourselves things like: “Just how miserable will the Fourth of July be in 2100?”

We’re fun like that.

But really, our summers are hot and getting hotter. Just ask the founding fathers: On July 4, 1776, Thomas Jefferson dressed and bewigged himself for a long day of declaration-adopting in a relatively pleasant 76 degrees — good news for the thirteen waistcoat-clad dudes in the stuffy halls of Philadelphia’s State House.