It looks like calendula to me. I thought it didn't like hot weather though. It bloomed all winter? Where do you live? You don't need to be specific. Also if you are going to discuss garden stuff it helps to know your zone.

I was going to guess calendula too but the winter thing through me.

Thank you! I live in central Arkansas. It was so hot last summer everything died except this guy and even when we had a snow/ice storm this past winter it just kept going. It wasn't constantly in bloom but it held up. I am going to look for more seeds this weekend. Un-killable is a perfect plant for me.. :) Again Thank you!

Have you tried to collect seeds from that plant just in case?
It may reseed on its own so watch for seedlings if you've been leaving the flowers.
I'll post a link to a how-to on collecting calendula seeds that has a photo of the seeds.

Here is a link that might be useful: How to collect calendula seeds