Sometimes it's right on the box of rice mix—the high altitude version of cooking instructions. Usually this means that your rice will have to cook a little bit longer if you are in Denver or at the top of Mount Everest. Of course that's just a joke. No one cooks rice at the top of Everest. But why are the instructions even different? Why does it matter where you cook? The answer has to do with boiling water. Go ask some people on the street about the boiling temperature of water.