Hi,
Humidity refers to the level of water content in the atmosphere.
Solid bodied guitar, i.e electrics, are not so much affected by humidity.
Acoustic guitars with a solid top, or full solid acoustics are very much affected by humidity.
Ideal humidity level for our prized musical instruments is 50-60%.
Because I have a hygrometer in my house, I can tell you accurately that Singapore's humidity level is 75-80%. Which, in other words, is very humid and wet.
Too humid, and your acoustic will warp and belly. And it will also sound damp and heavy, that's because of the water content in the wood.
Too dry, and your guitar will start to crack. By dry I mean below 45%.
So, when it's too humid, you use a dehumidifier. Products like Zorb-It, Thirsty Hippo, Silica Gel satchets, or a dehumidifier are things you need.
I personally use Zorb-It. Although it has to be said that nothing beats a proper electrical dehumidifier.
In dry countries, you need the opposite. A humidifier. Products like the Humistat are things you need.
