In the United States a day is considered hot when the temperature breaches 100 degrees Fahrenheit. In the rest of the world, the temperature is still in the 30's Celsius. But don't assign emotional value to that comparison because there are other measures of temperature too, like: Kelvin, Rankine, Newton, etc. No matter the measure, the objective temperature does not change, but when gazing at a thermometer subjective temperature can change.