The baby’s body temperature at night is lower than during the day is generally due to the baby’s limited ability to regulate body temperature or the difference in basal metabolism between day and night. 1. The baby’s thermoregulatory center, sweat glands, skeletal muscles, etc. are not yet well developed, and the subcutaneous fat is also very thin, so the baby’s body temperature is easily affected by the surrounding environment. Generally the night temperature is lower than the daytime temperature, the baby’s temperature will also change because of the temperature change of the external environment, the night body temperature is lower than the daytime body temperature. 2. When the baby’s basal metabolic rate is high, energy consumption increases and so does body temperature. Generally speaking, the baby’s daytime activity is greater than at night, the basal metabolic rate is also greater than at night, so the baby’s body temperature will be higher during the day and lower at night. If your baby’s body temperature is lower at night than during the day, and if it is accompanied by other discomforts, or if the temperature itself is abnormal, there may be other reasons, so it is recommended that you go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, and then give targeted treatment or therapy under the guidance of the doctor.