For those of you who artificially incubate your eggs, one of the most important aspects of doing so is to not only control but more importantly accurately monitor the temperature and humidity in your incubator. One of the oldest, most reliable and most accurate ways of doing so is using a wet and dry bulb. Or more clearly stated, a calibrated thermometer for measuring temperature and a calibrated thermometer with a wick and water source for measuring humidity. This video should give you a quick answer to the question what is a wet bulb?
Once you have an understanding of what we are talking about when you hear wet and dry bulb, the next step is to put them to use. After acquiring your dial meat thermometers (or if using an older setup with alcohol or mercury thermometers) you will then want to learn how to calibrate a thermometer.
Finally, after you have your wet and dry bulbs calibrated and situated in your incubator, this nice little chart will serve good referenceto take your wet and dry bulb readings and convert them into relative humidity percentage.