Out of the blue I went to start my car and the battery was dead. I charged it, then my wife and I took it out shopping and to dinner and everything seemed fine. This morning I went out to start the car and once again the battery was dead. Both times I had made sure nothing was left on and after charging the battery again, I put it in to make sure there was not light that was staying on by itself etc.. Any suggestions on what will drain the battery over night?

Hopefully, this will help you locate the source of the drain:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-honda-civics-46563-3.html#post241804