Well, winter is upon us again in the northeast. As we bundle up into gloves, wool hats and layer up in sweaters and down jackets, it seems to be a good time to talk about caring of your instrument.
IN THE CAR
My general rule is this: do not treat your guitar the way you would any other living being. Would it be safe to leave a person in the trunk of the family car on a 10 degree evening? Probably not. While your instrument might not suffer in the same way a living creature would, it is sensitive to humidity and temperature, and extreme damage could happen, including cracks in the wood, and separation at the seems. This would be a tragic fate for your cherished axe.
COMING IN FROM THE OUTDOORS
It's a wise idea to let your guitar stay in the case when you first come in from a particularly cold day. I generally leave my guitar in its hard shell case for an hour or so before I feel comfortable opening the case. I have heard horror stories of the finish cracking when a cold instrument is suddenly blast with the warm air of a heated house. Luckily, I have not experienced this myself.
HEAT AND DRAFTY WINDOWS
I generally avoid leaving my guitar near baseboard heat, and drafty windows. Maybe I am being overly cautious, but the last thing I want is my guitar drying out and cracking. Many people leave their instruments in the case during the winter with a humidifier for this reason. I myself like to keep it on the stand. Guitars are work of arts, and every time I walk by one, I want to play it. This helps my practicing a bunch. I am a firm believer of out of sight, out of mind!
SETUP AND RESTRINGING
Lastly, guitars will shift with the temperature and humidity. This is called "action" on a guitar, which in short means "how far away are the strings from the fretboard". Going into what a setup entails would be beyond the scope of this article, but let's just say, if you do not know how to do your own setups, it's worth bringing your guitar to a competent tech every time there is a significant change in weather. This should cost roughly $50 per guitar. Living in an area of the country where the weather changes so much, I taught myself how to do setups. Owning 10+ guitars at any given time, its been worth the investment of time and modest amount of tools.
I have also noticed that my strings die quickly if I leave them in the cold for an extended period of time, especially on my acoustic guitars. String changes should happen at least once a month anyways, but it's worth changing them out more often if you are constantly bringing your guitar in and out of the cold.
So there you have it. As long as you use some common sense, you should be fine. When in doubt, just imagine your guitar as a living creature, and you should never have any major problems with your instrument. Happy practicing!