WEATHER AND CLIMATE 137 



SUMMARY 



Any discussion of the weather takes account of temperature, humid- 

 ity, winds, precipitation, and the state of the sky as to cloudiness. 

 While the weather at any place may vary from day to day, even from 

 hour to hour, the climate of any region on the other hand is an average 

 of the weather conditions through long periods of time, and it changes 

 but little. 



Personal well-being and self preservation alike demand that the 

 weather be taken into account in the affairs of life. Making provision 

 against weather changes, and any unfavorable conditions incident to 

 these changes, constitutes one of the chief incentives for thrift and 

 resourcefulness in individuals. It is a large factor in making and main- 

 taining the enlightenment and progress of nations. 



Suitable changes in diet, clothing, and activities should accompany 

 changes in weather in order to adjust the manner of life to prevailing 

 conditions. Failure to do this is likely to involve waste, lack of effi- 

 ciency, and risks to health and to life itself. 



It is likely that nervous temperaments may at times be seriously 

 affected by weather conditions unusually prolonged, resulting in some 

 cases in depression of spirits and at other times in undue exhilaration. 



Where the humidity of the air is high in summer there is enough of 

 interference with the vaporization of perspiration to cause discomfort. 

 If extreme, this condition may imperil life by an unduly high tempera- 

 ture in the body. Heat prostrations do not necessarily imply exposure 

 to the direct rays of the sun. 



W T eather forecasts to be of value must take into account existing 

 conditions over relatively large areas. They demand a skilled inter- 

 pretation of these conditions. The forecasts are based upon "laws" 

 of the weather, or general statements concerning weather changes. 

 These laws have been verified from weather records extending over 

 long periods of observation. 



WEATHER AS AFFECTED BY HIGHS AND Lows 



In the central west of the United States where typical 

 weather conditions due to highs and lows are the rule, the 

 moisture-laden winds may be considered as coming from the 

 Gulf of Mexico. They commonly enter the southeast 



