I am a semi-observant Jew living in a neighborhood of extremely observant Jews, so I spend a lot of time watching and thinking of the things I see and hear. I have a question:

Is there a specific commandment in Torah concerning the covering of one's head at ALL times? I wear a yarmulka at temple, during other ceremonies such as unveilings, or when I pray. I consider this a tradition, not a commandment. Am I correct?

Thank you for your consideration