Is temperature "different" at altitude? I know the boiling point of water is lower at higher altitude. But a friend of mine says that temperature in general is different at altitude. So, if the cooking instructions say to bake something at 425, he says you should set the temperature of the oven higher to adjust for higher altitude. I say that temperature is an absolute that does not change with altitude. So an oven set to 425 at sea level has the same heating effect as an oven set to 425 at 4000 ft. This assumes we preheat the oven before placing the food in it. So, who's right?