Keeping a proper range of relative humidity is very important for both the taste and structural integrity of your cigars. A safe humidity range for most cigars will be between 65 and 70%, which is higher than the relative humidity often found at room temperatures. Keeping your cigars at room temperature & humidity is not advisable. Lower humidity tends to reduce the flavor in a cigar or even dry it out entirely, which could damage the cigar. It needs to be at a higher humidity in order to maintain the oils on the cigar leaves that make up the wrapper. However, you don’t want the humidity to be too high, either. Higher humidity will risk damaging your cigar with mold growth, or even making your cigar too moist to be lit properly.
A hygrometer will help you determine if your humidor has the right humidity for your cigars. The hygrometer is measuring relative humidity inside your humidor. This measurement is a percentage, indicating how saturated the air is with water vapor. Of course, in order for the device to be useful, you need to know how to read a hygrometer.
Reading your hygrometer will depend on which model you are using. Almost every single analog hygrometer uses a circular dial or gauge. The mechanical sensors inside the hygrometer move the needle along the gauge, so it points at the proper level of relative humidity. The dial's range is labeled on the hygrometers face. This range is often numbered by fives or tens to indicate the percentage of relative humidity. Simply see where the needle has lined up along this range to determine the relative humidity reading.
Digital hygrometers are often times far simpler to read, depending on their display structure. Most have a simple flat screen with a digital readout, showing only the number that is the reading, instead of simply showing the entire range and pointing. However, some digital hygrometer is our fashion to mimic the circular dial of an analog hygrometer, so a few models will still have a bar that points to the range. Unlike analog hygrometers, this bar is often a digital line on the readout, instead of a physical needle that moves. While this feature offer is a fun and modern take on the old style of display, this is the exception rather than the rule, and more often than not you will simply see just the number for the readout displayed on the digital hygrometer's screen.
Both analog and digital hygrometers have received criticism for being inaccurate. Most hygrometers that are brand new will be off by a little bit, so no matter what the manufacturer says about being pre-calibrated, always calibrate your hygrometer before using it. There is no better way to make sure that it is giving you an accurate reading then to calibrate it yourself. You can use either a calibration kit or the salt test in order to calibrate your hygrometer. Once your hygrometer is calibrated, it will provide a readout that will help you keep your cigars in prime condition.