Possible causes of recurrent hypothermia in infants include summer fever due to immature development of the body temperature center and blood system diseases. 1. Summer fever: As the thermoregulatory center of the brain is developing, the thermoregulatory ability of newborn babies is not yet perfect, so they may have recurrent low-grade fever in summer. 2. Diseases: Some hematologic diseases such as lymphoma, leukemia, and tuberculosis, etc., may cause recurrent low-grade fever, but this low-grade fever is usually accompanied by anemia, weight loss, infectious manifestations and other symptoms. In addition, hyperthyroidism may also cause recurrent low-grade fever. Babies with recurrent low-grade fever are advised to go to the hospital in time for routine blood tests and timely treatment if the disease exists.