How does the amount of water vapor in the air change the temperature ?

Expert Answers
bandmanjoe eNotes educator| Certified Educator

The amount of water vapor in the air can have an effect on increasing temperature by taking longer to heat up.  Once the water vapor has this heat, it takes longer to release the heat, resulting in warmer temperatures at night, when the sun has gone down.  Another way the amount of water vapor influence temperature is a thing called the heat index.  This is the relationship that exists between the amount of heat in the air and the amount of releative humidity in the air.  When the relative humidity is high, water, in the form of sweat, evaporates at a slower rate, making us feel hotter.  So a day where the temperature is actually at 95 degrees Fahrenheit can make the temperature feel as high as 10 degrees hotter, around 105 degrees Fahrenheit.  In the deep south, such as the states of Lousiana, Mississippi, Alabama, Georgia, and Florida, the relative humidity during the summer months takes a sharp spike, so heat indexes should be observed for health concerns.