1. How to Determine Dew Point and Relative Humidity

2. Aim: How to Determine Dew Point and Relative Humidity
I. Determining Dew Point and Relative Humidity
A. Find out dry bulb (air) temperature
B. Find out wet bulb temperature (Always cooler than dry bulb. If it is the same temperature you will have 100% relative humidity and the air is said to be saturated.

3. C. Subtract the wet bulb temperature from the dry bulb temperature (wet bulb depression).
D. Turn to your Dew Point or Relative Humidity Chart in your E.S.R.T.
1. Find your dry bulb temperature on the left side of the table.
2. Find your wet bulb depression on the top of the table.

4. 3. Follow the dry bulb temperature row until you hit the wet bulb depression column. This is your Dew Point or Relative Humidity reading. (Remember: Dew Point readings are in oC and Relative Humidity readings are in %).
E. What to do if you have an odd dry bulb temperature.
1. Find the even dry bulb values above and below your odd temperature. Ex: If the dry bulb reading is 9oC, look at 8oC and 10oC.

5. 2. Find out the values for each of the even temperatures.
3. Pick a value in between the even temperature values.

6. Daily Relative Humidity Changes