Short Answer
It affects your acoustic guitar quite a lot, in fact, and there are simple methods and products to help stabilize humidity and protect your precious wooden friends.
Long Answer
If you live in any place that experiences changes in humidity (or even humidity in general), you’ve got to consider that when it comes to caring for your acoustic guitar. If you don’t live in a place that doesn’t experience humidity – low or high – let us know where you’re at because that would probably save us all a lot of headaches. That’s a joke, though. Everywhere you go, you’ll have to deal with humidity, hate to break it to you.
Concerning places that experience noticeable changes in humidity (mainly temperate climates like the Atlantic Northeast), you have some work to do when it comes to the changes in seasons. If you’re in those kinds of climates, winters are dry and summers are humid. This factors into the care of your acoustic instrument because of changes in air humidity – the woods of acoustic guitars expand as they absorb moisture in the humid summer air and contract as they lose moisture in the dry winter air.
These changes in expansion and retraction can have a significant effect on the tonewoods in your acoustic guitar as they literally change in size. It’s no exaggeration that your acoustic guitar can break from changes in humidity alone if not cared for properly.
Let’s not despair, though, let’s be proactive.
There’s a host of products you can buy to upkeep the correct humidity with your acoustic guitar all throughout the year. These products are easy to use and fairly cheap. Think of it this way: a couple bucks now or a completely new acoustic guitar later?