There are those lovely sunny days where the sky is blazingly blue and the air wafts with the scent of barbecues. Then there are those days that are so stiflingly, throat-burningly hot that you daren’t even open a window. The kind of heat that can turn people into sweaty messes within seconds. Even the northernmost parts of the US have experienced such extreme heat. We reveal the record high in every state, from the (relatively) coolest to the hottest ever day in the USA.