Possible causes of headache in hot weather include insufficient blood supply to the brain, migraine and pyrexia. 1. Insufficient blood supply to the brain, when the weather is hot, the peripheral blood vessels of the whole body expand and become congested, and the blood volume of the body decreases, thus leading to insufficient blood supply to the brain and thus generating headaches. 2. Migraine, also known as vascular headache. Temperature changes can cause intracranial and extracranial vascular episodes of contraction and relaxation dysfunction, there will be severe head pain. 3. Pyrexia, also known as heat stroke, when the weather is too hot, can not be timely heat out of the body, excessive accumulation of heat in the body, which will lead to damage to the nerve organs, thus triggering a headache. When the symptoms of headache, it is recommended to consult a doctor in time to find out the cause of the disease, symptomatic treatment.