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 a 1983 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( 气压 ) 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 .