Why does my temperature fluctuate?

Your body temperature fluctuates by up to 0.9 °F throughout the day. This is perfectly normal. In the morning, your temperature is usually lower than in the late afternoon or evening. 

Other natural fluctuations for example occur due to physical activity or due to different phases of the menstrual cycle. 

In children, the body temperature often fluctuates more, as they are not yet able to regulate their body temperature properly. They also sweat significantly less and later than adults.