How often do I need to calibrate a hygrometer?
Every six months.
Over time, ALL hygrometers need to be calibrated to make sure their readings stay true. In professional laboratories, hygrometers are regularly calibrated.
The easiest and most accurate way to calibrate a hygrometer is with the Boveda One-Step Hygrometer Calibration Kit. Takes just 24 hours for professional-level results. Order the calibration kit for humidors here.