There is a term for what you are experiencing: FUO, fever of unknown origin. Unfortunately, the only way to diagnose the problem is by eliminating everything else that could be causing it. It can be a long process that involves a lot of time and tests with the doctor. I have no idea if you should be concerned or not. If it worries you, worsens, or if you develop new symptoms, you should make an appointment with your physician.

I agree that a doctor is going to need to run some tests. He or she will also ask a lot of questions.Do you just feel hot or do you always take your temperature? Does the temperature vary, sometimes higher than others? The fact that it's the same time every day could be due to something you are doing at the time. You said it's when you come home. If you came home later, would the fever come on when you got home or before? How long does the fever last?

Are you having any other symptoms? Did you have any symptoms when this first started? Cough, congestion, headache, nausea, etc. Have you missed any periods?