Alright, I did a little searching and found some helpful links for you (and me). These may help answer your question. : )



Relative humidity
Relative humidity is the ratio of the partial pressure of water vapor in an air-water mixture to the saturated vapor pressure of water at a prescribed temperature. The relative humidity of air depends on temperature and the pressure of the system of interest.
[link to en.wikipedia.org]

Check out the "Comfort" section in that ^^^^ link...


What is relative humidity and how does it affect how I feel outside?
[link to science.howstuffworks.com]

I found that ^^^ link helpful...


The Heat Index Chart
The Heat Index is a function of temperature and relative humidity. The combination of the two results in an apparent temperature which gives an idea of what it would feel like under normal-to-low humidity conditions.
[link to www.weather.com]


Heat index
The heat index (HI) or humiture or humidex (not to be confused with the Canadian humidex) is an index that combines air temperature and relative humidity in an attempt to determine the human-perceived equivalent temperature—how hot it feels. The result is also known as the "felt air temperature" or "apparent temperature". For example, when the temperature is 32 °C (90 °F) with very high humidity, the heat index can be about 41 °C (106 °F)

The human body normally cools itself by perspiration, or sweating. Heat is removed from the body by evaporation of that sweat. However, relative humidity reduces the evaporation rate because the higher vapor content of the surrounding air does not allow the maximum amount of evaporation from the body to occur. This results in a lower rate of heat removal from the body, hence the sensation of being overheated. This effect is subjective; its measurement has been based on subjective descriptions of how hot subjects feel for a given temperature and humidity. This results in a heat index that relates one combination of temperature and humidity to another one at higher temperature and lower humidity.
[link to en.wikipedia.org]

Check out the "Table of Heat Index values" section in that ^^^^ link. That shows you what the temperature "feels" like based on the air temperature and relative humidity.

I hope this helped a little.