Yes, a child's stammer can change throughout the days and weeks and across different situations.
Health issues, such as illness and tiredness, can lead to more moments of stammering. Equally, how a child feels about speaking in different situations, such as on the phone or in front of groups, can change how their stammer presents. This can also be linked to emotions of anxiety, excitement and confidence.
The way that a child's stammer varies or fluctuates will not follow the same pattern in all children and young people. For example, one child may stammer more when asked questions in class whilst another might stammer more when they are happy, relaxed and excited chatting to friends in the playground.