1. It’s not the heat, it’s the humidity.

2. What is humidity?
Humidity is the amount of water dissolved in the air.
Humidity can be talked about in three ways:
Absolute Humidity
Specific Humidity
Relative Humidity

3. Absolute Humidity
Absolute humidity is the density of water in the air.
It is usually measure in grams of water vapor per cubic meter of air.

4. Specific Humidity
Specific humidity tells us how much of the air is water vapor.
It is expressed as the mass of water divided by the total mass of water and air.

5. Relative Humidity
Relative humidity tells us how close the air is to being saturated with water vapor.
Relative humidity if found by dividing the amount of water in the air by the maximum amount of water that could dissolve at the current temp.

6. Relative Humidity Relative humidity is used more than the others.
It is useful in predicting when it will rain.
It also helps to determine how hot it feels.

7. Relative Humidity Our bodies try to stay cool by sweating.
Sweat on our skin uses some of the body’s heat to evaporate.
If the relative humidity is high (the air is close to being saturated with water), it is harder for the sweat to evaporate.

8. Dew Point
The dew point is the temperature at which the air would be saturated, with it’s current amount of water.
Warm air dissolves more water just like warm water dissolves more sugar.
The name comes from it being the temperature dew (condensation) would form if the air was cooled.
If the dew point is below 0°C, it is sometimes called the frost point.

9. Dew Point
If the air temperature is close to the dew point, we are more likely to have rain, snow, fog, or other precipitation.