Relative humidity (RH) is a percentage. In a humidor it is the figure people argue about. Too low and cigars dry, crack, and burn hot. Too high and draw gets tight, burn gets lazy, and mold risk climbs. Temperature rides along; warm wet air is a worse idea than cool wet air.
Commonly cited working ranges sit around 65–72% RH. The old “70 percent, 70 degrees” rule is a starting slogan, not a law. Some storage programs for Cuban cigars prefer the mid-to-high 60s and a cooler room. This site does not pick a winner. Hold a number in that band and keep it still. See the humidor article.
Calibrate the hygrometer. An analog needle that has never seen a salt test is a decoration.