The possible reasons for a toddler’s fever at night and normal during the day include special infection, temperature difference in physical cooling, and drug failure. 1. Special infections: when there are other types of infections in the body of young children, such as tuberculosis mycobacterium infection, the general daytime relative symptoms are not obvious, the phenomenon of fever will appear at night, so it will cause fever at night in the daytime normal situation. 2. Physical cooling there is a temperature difference: during the day, young children may increase the amount of exercise and lead to increased water intake, the physical cooling effect is better, the body temperature in the daytime will remain balanced, while the night may be due to the high temperature of the room, resulting in the physical cooling effect is poor, which will lead to the formation of young children fever at night during the day the phenomenon of normal. 3. Drug failure: some children eat cold medicine containing fever-reducing ingredients during the day, the effect of the medicine over, the fever symptoms at night. The fever at night and normal during the day, there may be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.