1.The time of occurrence of headache is helpful to analyze the cause of headache. Knowing the time of occurrence of headache is also helpful to analyze the cause of headache. For example, headaches caused by intracranial occupational lesions are usually more intense when waking up in the early morning, and some patients can even wake up from sleep with pain because the intracranial pressure is relatively high when lying down at night. In frontal sinusitis or sieve sinusitis, because of lying down at night, inflammatory secretions accumulate in the sinus cavity, so the headache can be heavier in the early morning, while in the afternoon, due to the position and gravitational drainage, the secretions are discharged from the sinus cavity in the form of pus nasal discharge, which reduces the stimulation of purulent secretions to the sinus wall erectile membrane and other factors, and the headache can be relieved. Trigeminal neuralgia occurs more often during the day, while cluster headache occurs more often at night during sleep and tension headache is seen in the late afternoon to evening time. The duration of the headache is also important to understand the cause of the headache. Headaches that occur quickly and are short in duration are often functional disorders, such as primary trigeminal neuralgia and vascular migraine. Trigeminal neuralgia lasts for a short period of time, seconds or tens of seconds. Migraines can last 2 to 3 hours or 1 to 2 days. Headaches caused by lesions in some organs of the head (e.g. otogenic, rhinogenic, paranasal sinus, odontogenic headaches) or pain after lumbar puncture can last for several days or longer. Chronic persistent headache is mostly caused by organic lesions, such as brain tumors, increased intracranial pressure, subdural hematoma, etc., which can manifest as persistent progressive headache. Of course, there are exceptions, such as headache caused by neurosis, which can be continuous for years and months, changing with personal emotion, environment and various factors inside and outside the body, but the degree of headache is often mild and can be tolerated by patients. 2.The effect of seasonal changes on headache Some patients who often suffer from headache sometimes figure out some rules for their disease. Sometimes, they will tell others or doctors that they often have headache every year in spring and summer. According to epidemiological surveys, some headaches, such as vascular headaches, do have some relationship with the seasons, especially in summer when the temperature rises, which is most likely to trigger migraine attacks. In addition to hot weather and easy expansion of blood vessels, long days and short nights and insufficient sleep time are also among the causes that trigger migraine. Some scholars point out that migraine is easily triggered by less than 6 hours of sleep per day. In addition, in spring and summer, more rain, hot and humid weather and lower air pressure are also triggering factors for migraine. This shows that climate change does have a place among the many triggering factors of migraine. Other headaches, such as trigeminal neuralgia, are most likely to develop in late fall and early winter when the temperature drops. Similarly, stroke is also related to seasonal climate, i.e., the lower the temperature and the higher the air pressure, the higher the incidence of hemorrhagic stroke, because the severe climate can disrupt the normal vascular regulation in the body, and the sudden cold climate can stimulate the excitability of sympathetic nerves and increase the secretion of substances such as norepinephrine and catecholamines in the body, which can cause vasoconstriction of small arteries and increase the blood pressure, resulting in Therefore, the headache caused by hemorrhagic stroke is naturally linked to the seasonal changes. In addition, in the winter season, many people close their doors and windows and heat their homes around the stove, which makes it easy for carbon monoxide poisoning (gas poisoning) to occur, and the resulting headaches are also high in winter. And in summer, due to working in the fields under the hot sun or workshop_work, it is easy to have heat stroke, which can also cause headache. The organic headache caused by tumor, trauma, infection, etc. has no obvious relationship with season and climate.