Humidity, or relative humidity, measures the quantity of water vapor in the air. Have you ever stepped outdoors and felt a “heavy” or dampness in the air? This is how greater humidity feels.
An increase in atmospheric temperature allows for more moisture retention, and this phenomenon occurs. Wherever you keep your equipment, you should monitor this measurement, which you may see in the weather app on your phone.
Guitars should not be exposed to high or low humidity for extended periods. Rapid changes in humidity can also be problematic.
https://zagerguitar.com/blog/h....ow-to-humidify-a-gui