Humidity

My friend Paul in England regularly goes to Florida for vacations.  There can't be many more extremes of climate than these two places.  He once explained to me the effect of humidity on temperature, which naturally I didn't "get."  So I asked him to put it down for me.  Here it is.

Why does it feel hotter one day compared to another when the temperatures were identical? Why do weather reports often include the phrase: "feels like" after the temperature figure? The answer to both those questions is: Humidity. But what is it?
Relative humidity is the most common measurement of humidity used by weather forecasters. Simply, it is the amount of water in the air - the higher the amount of water in the air the higher the humidity. A reading of 100 per cent humidity does not mean it’s raining but it does mean the air can hold no more water.
Why does humidity affect us? Well, humans are very sensitive to humidity levels because the skin relies on air to get rid of sweat. If the humidity level is high the sweat will not evaporate so easily or at all. Consequently, we feel much hotter when the relative humidity is high. Conversely, if the humidity is low, humans can feel cooler than the air temperature. It is generally agreed that people feel most comfortable at a relative humidity of around 45 per cent.
Examples:
Air Temp:    Humidity per cent
Degrees F  90%  70%  50%  40%

                          Feels Like

      80         85      82    80      79

      85        101     92    86      84

      90        121    105   94      89