Different weather makes people feel different. It influences health, intelligence ( 智力 ) and feelings. In August, it is very hot and wet in the southern part of the United States. People there have heart trouble and other kinds of health problems during this month. In the northeast and the middle west, it is very hot sometimes and very cold sometimes. People in these states have more heart trouble after the weather changes in February or March. The weather can also influence intelligence.For example, in 1983 a study by scientists showed that the IQ of a group of students was very high when a very strong wind came , but after the strong wind, their IQ was 10% lower.The wind can help people have more intelligence. Very hot weather, on the other hand, can make it lower. Students in many schools of the United States often do worse on exams in the hot months of the year ( July and August ) . Weather also has a strong influence on people ' s feelings. Winter may be a bad time for thin people. They usually feel cold these months. They might feel unhappy during cold weather. But fat people may have a hard time in hot summer. At about 18°C , people become stronger. Low air pressure may make people forgetful. People leave more bags on buses and in shops on low ­ pressure days. There is “ good weather ” for work and health. People feel best at a temperature of about 18 °C . Are you feeling sad, tired, forgetful or unhappy today? It may be the weather ' s fault.