The Daily Time:

The cupping operation is usually performed in the early morning after the sunrise, but the time of stopping it in each day is pointed according to the heat level of the weather. If the weather stills moderate during the day, we continue applying it until noon; such timing is permissible but not desirable.

It is better for cupping to be performed at the first hours of the day (because cupping must be performed while the person is still without having breakfast).

If a person remains without having breakfast for late hours of the day, he becomes tired and dizzy for the delay of having his breakfast and having performed the cupping operation. In order to avoid all these problems and to perform a correct useful cupping operation, we must hasten to perform it in the early hours of the day from seven o’clock till ten o’clock, and in a needful situation when the time is the last day (27 of the lunar calendar) of performing it and the weather is still moderate and not intense in heat, in this case you can perform the operation until eleven o’clock or more before the noon. When we delay the operation until (midday), we certainly walk, move and work.

This motivates the blood circulation a little and scoops with it the harmful precipitations (such as cell ghosts and dead red blood cells ...) which temporary precipitate under the shoulder blades, eventually the benefit from cupping is not complete.