You are taller in the morning than in the evening.
Do you know that your height changes from morning to evening ?
It's called "Diurnal Variation" (variation in various body systems that occurs in a 24 hours natural body cycle).
When you wake up in the morning, you are tallest. On an average, you are approximately one half inch taller when you wake in the morning. The reason is that, during the night when you are in horizontal position, the fluid in the body enters your spinal discs and they expand. Because of this you are taller when you wake up in the morning.
During the day your body has to deal with the stress of standing, the various factors like gravity, blood circulation casue the discs to loose fluid and they become compressed as the fluid seeps out. This results in your losing a small amount of extra height.