No hot water in shower only in morning?

In the morning and afternoon the two showers in my apartment will only get lukewarm, even though the faucets will get hot. At night, the showers will get just hot enough to take a comfortable shower but still the temperature is short of what the hottest tap water should be.

Do you know what could be causing this? I live in a small apartment building: only three units each on its own floor, and each with its own water heater.

It sounds like you have temperature limiters on your shower valves
Post pictures and I may be able to tell you how to bump them up.
Each brand has a different way of doing this.